-; RUN: llc < %s -asm-verbose=false | FileCheck %s
+; RUN: llc < %s -asm-verbose=false -disable-block-placement -verify-machineinstrs | FileCheck %s
+; RUN: llc < %s -asm-verbose=false -verify-machineinstrs | FileCheck -check-prefix=OPT %s
; Test the CFG stackifier pass.
-target datalayout = "e-p:32:32-i64:64-n32:64-S128"
+target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
target triple = "wasm32-unknown-unknown"
declare void @something()
; CHECK-LABEL: test0:
; CHECK: loop
+; CHECK-NOT: br
; CHECK: i32.add
-; CHECK: br_if
+; CHECK-NEXT: i32.ge_s
+; CHECK-NEXT: br_if
+; CHECK-NOT: br
; CHECK: call
-; CHECK: br BB0_1{{$}}
+; CHECK: br 0{{$}}
; CHECK: return{{$}}
+; OPT-LABEL: test0:
+; OPT: loop
+; OPT-NOT: br
+; OPT: i32.add
+; OPT-NEXT: i32.ge_s
+; OPT-NEXT: br_if
+; OPT-NOT: br
+; OPT: call
+; OPT: br 0{{$}}
+; OPT: return{{$}}
define void @test0(i32 %n) {
entry:
br label %header
; CHECK-LABEL: test1:
; CHECK: loop
+; CHECK-NOT: br
; CHECK: i32.add
-; CHECK: br_if
+; CHECK-NEXT: i32.ge_s
+; CHECK-NEXT: br_if
+; CHECK-NOT: br
; CHECK: call
-; CHECK: br BB1_1{{$}}
+; CHECK: br 0{{$}}
; CHECK: return{{$}}
+; OPT-LABEL: test1:
+; OPT: loop
+; OPT-NOT: br
+; OPT: i32.add
+; OPT-NEXT: i32.ge_s
+; OPT-NEXT: br_if
+; OPT-NOT: br
+; OPT: call
+; OPT: br 0{{$}}
+; OPT: return{{$}}
define void @test1(i32 %n) {
entry:
br label %header
; Test that a simple loop is handled as expected.
; CHECK-LABEL: test2:
-; CHECK: block BB2_2{{$}}
-; CHECK: br_if {{.*}}, BB2_2{{$}}
-; CHECK: BB2_1:
-; CHECK: br_if $pop{{[0-9]+}}, BB2_1{{$}}
-; CHECK: BB2_2:
+; CHECK-NOT: local
+; CHECK: block{{$}}
+; CHECK: br_if {{[^,]*}}, 0{{$}}
+; CHECK: .LBB2_1:
+; CHECK: br_if ${{[0-9]+}}, 0{{$}}
+; CHECK: .LBB2_2:
; CHECK: return{{$}}
+; OPT-LABEL: test2:
+; OPT-NOT: local
+; OPT: block{{$}}
+; OPT: br_if {{[^,]*}}, 0{{$}}
+; OPT: .LBB2_1:
+; OPT: br_if ${{[0-9]+}}, 0{{$}}
+; OPT: .LBB2_2:
+; OPT: return{{$}}
define void @test2(double* nocapture %p, i32 %n) {
entry:
%cmp.4 = icmp sgt i32 %n, 0
}
; CHECK-LABEL: doublediamond:
-; CHECK: block BB3_5{{$}}
-; CHECK: block BB3_2{{$}}
-; CHECK: br_if $pop{{[0-9]+}}, BB3_2{{$}}
-; CHECK: block BB3_4{{$}}
-; CHECK: br_if $pop{{[0-9]+}}, BB3_4{{$}}
-; CHECK: br BB3_5{{$}}
-; CHECK: BB3_4:
-; CHECK: BB3_5:
+; CHECK: block{{$}}
+; CHECK-NEXT: block{{$}}
+; CHECK: br_if ${{[^,]*}}, 0{{$}}
+; CHECK: br 1{{$}}
+; CHECK: .LBB3_2:
+; CHECK-NEXT: end_block{{$}}
+; CHECK: block{{$}}
+; CHECK: br_if ${{[^,]*}}, 0{{$}}
+; CHECK: br 1{{$}}
+; CHECK: .LBB3_4:
+; CHECK-NEXT: end_block{{$}}
+; CHECK: .LBB3_5:
+; CHECK-NEXT: end_block{{$}}
; CHECK: return ${{[0-9]+}}{{$}}
+; OPT-LABEL: doublediamond:
+; OPT: block{{$}}
+; OPT-NEXT: block{{$}}
+; OPT: br_if ${{[^,]*}}, 0{{$}}
+; OPT: block{{$}}
+; OPT: br_if ${{[^,]*}}, 0{{$}}
+; OPT: br 1{{$}}
+; OPT: .LBB3_4:
+; OPT: .LBB3_5:
+; OPT: return ${{[0-9]+}}{{$}}
define i32 @doublediamond(i32 %a, i32 %b, i32* %p) {
entry:
%c = icmp eq i32 %a, 0
}
; CHECK-LABEL: triangle:
-; CHECK: block BB4_2{{$}}
-; CHECK: br_if $pop{{[0-9]+}}, BB4_2{{$}}
-; CHECK: BB4_2:
+; CHECK: block{{$}}
+; CHECK: br_if $1, 0{{$}}
+; CHECK: .LBB4_2:
; CHECK: return ${{[0-9]+}}{{$}}
+; OPT-LABEL: triangle:
+; OPT: block{{$}}
+; OPT: br_if $1, 0{{$}}
+; OPT: .LBB4_2:
+; OPT: return ${{[0-9]+}}{{$}}
define i32 @triangle(i32* %p, i32 %a) {
entry:
%c = icmp eq i32 %a, 0
}
; CHECK-LABEL: diamond:
-; CHECK: block BB5_3{{$}}
-; CHECK: block BB5_2{{$}}
-; CHECK: br_if $pop{{[0-9]+}}, BB5_2{{$}}
-; CHECK: br BB5_3{{$}}
-; CHECK: BB5_2:
-; CHECK: BB5_3:
+; CHECK: block{{$}}
+; CHECK: block{{$}}
+; CHECK: br_if $1, 0{{$}}
+; CHECK: br 1{{$}}
+; CHECK: .LBB5_2:
+; CHECK: .LBB5_3:
; CHECK: return ${{[0-9]+}}{{$}}
+; OPT-LABEL: diamond:
+; OPT: block{{$}}
+; OPT: block{{$}}
+; OPT: br_if {{[^,]*}}, 0{{$}}
+; OPT: br 1{{$}}
+; OPT: .LBB5_2:
+; OPT: .LBB5_3:
+; OPT: return ${{[0-9]+}}{{$}}
define i32 @diamond(i32* %p, i32 %a) {
entry:
%c = icmp eq i32 %a, 0
; CHECK-LABEL: single_block:
; CHECK-NOT: br
; CHECK: return $pop{{[0-9]+}}{{$}}
+; OPT-LABEL: single_block:
+; OPT-NOT: br
+; OPT: return $pop{{[0-9]+}}{{$}}
define i32 @single_block(i32* %p) {
entry:
store volatile i32 0, i32* %p
; CHECK-LABEL: minimal_loop:
; CHECK-NOT: br
-; CHECK: BB7_1:
+; CHECK: .LBB7_1:
; CHECK: i32.store $discard=, 0($0), $pop{{[0-9]+}}{{$}}
-; CHECK: br BB7_1{{$}}
-; CHECK: BB7_2:
+; CHECK: br 0{{$}}
+; CHECK: .LBB7_2:
+; OPT-LABEL: minimal_loop:
+; OPT-NOT: br
+; OPT: .LBB7_1:
+; OPT: i32.store $discard=, 0($0), $pop{{[0-9]+}}{{$}}
+; OPT: br 0{{$}}
+; OPT: .LBB7_2:
define i32 @minimal_loop(i32* %p) {
entry:
store volatile i32 0, i32* %p
; CHECK-LABEL: simple_loop:
; CHECK-NOT: br
-; CHECK: BB8_1:
-; CHECK: loop BB8_2{{$}}
-; CHECK: br_if $pop{{[0-9]+}}, BB8_1{{$}}
-; CHECK: BB8_2:
+; CHECK: .LBB8_1:
+; CHECK: loop{{$}}
+; CHECK: br_if $pop{{[0-9]+}}, 0{{$}}
+; CHECK-NEXT: end_loop{{$}}
; CHECK: return ${{[0-9]+}}{{$}}
+; OPT-LABEL: simple_loop:
+; OPT-NOT: br
+; OPT: .LBB8_1:
+; OPT: loop{{$}}
+; OPT: br_if {{[^,]*}}, 0{{$}}
+; OPT-NEXT: end_loop{{$}}
+; OPT: return ${{[0-9]+}}{{$}}
define i32 @simple_loop(i32* %p, i32 %a) {
entry:
%c = icmp eq i32 %a, 0
}
; CHECK-LABEL: doubletriangle:
-; CHECK: block BB9_4{{$}}
-; CHECK: br_if $pop{{[0-9]+}}, BB9_4{{$}}
-; CHECK: block BB9_3{{$}}
-; CHECK: br_if $pop{{[0-9]+}}, BB9_3{{$}}
-; CHECK: BB9_3:
-; CHECK: BB9_4:
+; CHECK: block{{$}}
+; CHECK: br_if $0, 0{{$}}
+; CHECK: block{{$}}
+; CHECK: br_if $1, 0{{$}}
+; CHECK: .LBB9_3:
+; CHECK: .LBB9_4:
; CHECK: return ${{[0-9]+}}{{$}}
+; OPT-LABEL: doubletriangle:
+; OPT: block{{$}}
+; OPT: br_if $0, 0{{$}}
+; OPT: block{{$}}
+; OPT: br_if $1, 0{{$}}
+; OPT: .LBB9_3:
+; OPT: .LBB9_4:
+; OPT: return ${{[0-9]+}}{{$}}
define i32 @doubletriangle(i32 %a, i32 %b, i32* %p) {
entry:
%c = icmp eq i32 %a, 0
}
; CHECK-LABEL: ifelse_earlyexits:
-; CHECK: block BB10_4{{$}}
-; CHECK: block BB10_2{{$}}
-; CHECK: br_if $pop{{[0-9]+}}, BB10_2{{$}}
-; CHECK: br BB10_4{{$}}
-; CHECK: BB10_2:
-; CHECK: br_if $pop{{[0-9]+}}, BB10_4{{$}}
-; CHECK: BB10_4:
+; CHECK: block{{$}}
+; CHECK: block{{$}}
+; CHECK: br_if $0, 0{{$}}
+; CHECK: br 1{{$}}
+; CHECK: .LBB10_2:
+; CHECK: br_if $1, 0{{$}}
+; CHECK: .LBB10_4:
; CHECK: return ${{[0-9]+}}{{$}}
+; OPT-LABEL: ifelse_earlyexits:
+; OPT: block{{$}}
+; OPT: block{{$}}
+; OPT: br_if {{[^,]*}}, 0{{$}}
+; OPT: br_if $1, 1{{$}}
+; OPT: br 1{{$}}
+; OPT: .LBB10_3:
+; OPT: .LBB10_4:
+; OPT: return ${{[0-9]+}}{{$}}
define i32 @ifelse_earlyexits(i32 %a, i32 %b, i32* %p) {
entry:
%c = icmp eq i32 %a, 0
}
; CHECK-LABEL: doublediamond_in_a_loop:
-; CHECK: BB11_1:
-; CHECK: loop BB11_7{{$}}
-; CHECK: block BB11_6{{$}}
-; CHECK: block BB11_3{{$}}
-; CHECK: br_if $pop{{.*}}, BB11_3{{$}}
-; CHECK: br BB11_6{{$}}
-; CHECK: BB11_3:
-; CHECK: block BB11_5{{$}}
-; CHECK: br_if $pop{{.*}}, BB11_5{{$}}
-; CHECK: br BB11_6{{$}}
-; CHECK: BB11_5:
-; CHECK: BB11_6:
-; CHECK: br BB11_1{{$}}
-; CHECK: BB11_7:
+; CHECK: .LBB11_1:
+; CHECK: loop{{$}}
+; CHECK: block{{$}}
+; CHECK: block{{$}}
+; CHECK: br_if $0, 0{{$}}
+; CHECK: br 1{{$}}
+; CHECK: .LBB11_3:
+; CHECK: block{{$}}
+; CHECK: br_if $1, 0{{$}}
+; CHECK: br 1{{$}}
+; CHECK: .LBB11_5:
+; CHECK: .LBB11_6:
+; CHECK: br 0{{$}}
+; CHECK: .LBB11_7:
+; CHECK-NEXT: end_loop{{$}}
+; OPT-LABEL: doublediamond_in_a_loop:
+; OPT: .LBB11_1:
+; OPT: loop{{$}}
+; OPT: block{{$}}
+; OPT: block{{$}}
+; OPT: br_if {{[^,]*}}, 0{{$}}
+; OPT: block{{$}}
+; OPT: br_if {{[^,]*}}, 0{{$}}
+; OPT: br 2{{$}}
+; OPT: .LBB11_4:
+; OPT-NEXT: end_block{{$}}
+; OPT: br 1{{$}}
+; OPT: .LBB11_5:
+; OPT-NEXT: end_block{{$}}
+; OPT: .LBB11_6:
+; OPT-NEXT: end_block{{$}}
+; OPT: br 0{{$}}
+; OPT: .LBB11_7:
+; OPT-NEXT: end_loop{{$}}
define i32 @doublediamond_in_a_loop(i32 %a, i32 %b, i32* %p) {
entry:
br label %header
; Test that nested loops are handled.
+; CHECK-LABEL: test3:
+; CHECK: loop
+; CHECK-NEXT: br_if
+; CHECK-NEXT: .LBB{{[0-9]+}}_{{[0-9]+}}:
+; CHECK-NEXT: loop
+; OPT-LABEL: test3:
+; OPT: loop
+; OPT-NEXT: br_if
+; OPT-NEXT: .LBB{{[0-9]+}}_{{[0-9]+}}:
+; OPT-NEXT: loop
declare void @bar()
-
define void @test3(i32 %w) {
entry:
br i1 undef, label %outer.ph, label %exit
call void @bar()
br label %outer
}
+
+; Test switch lowering and block placement.
+
+; CHECK-LABEL: test4:
+; CHECK-NEXT: .param i32{{$}}
+; CHECK: block{{$}}
+; CHECK-NEXT: block{{$}}
+; CHECK-NEXT: block{{$}}
+; CHECK: br_if $pop{{[0-9]*}}, 0{{$}}
+; CHECK-NEXT: block{{$}}
+; CHECK: br_if $pop{{[0-9]*}}, 0{{$}}
+; CHECK: br_if $pop{{[0-9]*}}, 2{{$}}
+; CHECK-NEXT: .LBB13_3:
+; CHECK-NEXT: end_block{{$}}
+; CHECK-NEXT: return{{$}}
+; CHECK-NEXT: .LBB13_4:
+; CHECK: br_if $pop{{[0-9]*}}, 1{{$}}
+; CHECK: br_if $pop{{[0-9]*}}, 0{{$}}
+; CHECK-NEXT: return{{$}}
+; CHECK-NEXT: .LBB13_7:
+; CHECK-NEXT: end_block{{$}}
+; CHECK-NEXT: return{{$}}
+; CHECK-NEXT: .LBB13_8:
+; CHECK-NEXT: end_block{{$}}
+; CHECK-NEXT: return{{$}}
+; OPT-LABEL: test4:
+; OPT-NEXT: .param i32{{$}}
+; OPT: block{{$}}
+; OPT-NEXT: block{{$}}
+; OPT-NEXT: block{{$}}
+; OPT: br_if $pop{{[0-9]*}}, 0{{$}}
+; OPT-NEXT: block{{$}}
+; OPT: br_if $pop{{[0-9]*}}, 0{{$}}
+; OPT: br_if $pop{{[0-9]*}}, 2{{$}}
+; OPT-NEXT: .LBB13_3:
+; OPT-NEXT: end_block{{$}}
+; OPT-NEXT: return{{$}}
+; OPT-NEXT: .LBB13_4:
+; OPT: br_if $pop{{[0-9]*}}, 1{{$}}
+; OPT: br_if $pop{{[0-9]*}}, 0{{$}}
+; OPT-NEXT: return{{$}}
+; OPT-NEXT: .LBB13_7:
+; OPT-NEXT: end_block{{$}}
+; OPT-NEXT: return{{$}}
+; OPT-NEXT: .LBB13_8:
+; OPT-NEXT: end_block{{$}}
+; OPT-NEXT: return{{$}}
+define void @test4(i32 %t) {
+entry:
+ switch i32 %t, label %default [
+ i32 0, label %bb2
+ i32 2, label %bb2
+ i32 4, label %bb1
+ i32 622, label %bb0
+ ]
+
+bb0:
+ ret void
+
+bb1:
+ ret void
+
+bb2:
+ ret void
+
+default:
+ ret void
+}
+
+; Test a case where the BLOCK needs to be placed before the LOOP in the
+; same basic block.
+
+; CHECK-LABEL: test5:
+; CHECK: .LBB14_1:
+; CHECK-NEXT: block{{$}}
+; CHECK-NEXT: loop{{$}}
+; CHECK: br_if {{[^,]*}}, 2{{$}}
+; CHECK: br_if {{[^,]*}}, 0{{$}}
+; CHECK-NEXT: end_loop{{$}}
+; CHECK: return{{$}}
+; CHECK-NEXT: .LBB14_4:
+; CHECK: return{{$}}
+; OPT-LABEL: test5:
+; OPT: .LBB14_1:
+; OPT-NEXT: block{{$}}
+; OPT-NEXT: loop{{$}}
+; OPT: br_if {{[^,]*}}, 2{{$}}
+; OPT: br_if {{[^,]*}}, 0{{$}}
+; OPT-NEXT: end_loop{{$}}
+; OPT: return{{$}}
+; OPT-NEXT: .LBB14_4:
+; OPT: return{{$}}
+define void @test5(i1 %p, i1 %q) {
+entry:
+ br label %header
+
+header:
+ store volatile i32 0, i32* null
+ br i1 %p, label %more, label %alt
+
+more:
+ store volatile i32 1, i32* null
+ br i1 %q, label %header, label %return
+
+alt:
+ store volatile i32 2, i32* null
+ ret void
+
+return:
+ store volatile i32 3, i32* null
+ ret void
+}
+
+; Test an interesting case of a loop with multiple exits, which
+; aren't to layout successors of the loop, and one of which is to a successors
+; which has another predecessor.
+
+; CHECK-LABEL: test6:
+; CHECK: .LBB15_1:
+; CHECK-NEXT: block{{$}}
+; CHECK-NEXT: block{{$}}
+; CHECK-NEXT: loop{{$}}
+; CHECK-NOT: block
+; CHECK: br_if {{[^,]*}}, 3{{$}}
+; CHECK-NOT: block
+; CHECK: br_if {{[^,]*}}, 2{{$}}
+; CHECK-NOT: block
+; CHECK: br_if {{[^,]*}}, 0{{$}}
+; CHECK-NEXT: end_loop{{$}}
+; CHECK-NOT: block
+; CHECK: return{{$}}
+; CHECK-NEXT: .LBB15_5:
+; CHECK-NEXT: end_block{{$}}
+; CHECK-NOT: block
+; CHECK: .LBB15_6:
+; CHECK-NEXT: end_block{{$}}
+; CHECK-NOT: block
+; CHECK: return{{$}}
+; OPT-LABEL: test6:
+; OPT: .LBB15_1:
+; OPT-NEXT: block{{$}}
+; OPT-NEXT: block{{$}}
+; OPT-NEXT: loop{{$}}
+; OPT-NOT: block
+; OPT: br_if {{[^,]*}}, 3{{$}}
+; OPT-NOT: block
+; OPT: br_if {{[^,]*}}, 2{{$}}
+; OPT-NOT: block
+; OPT: br_if {{[^,]*}}, 0{{$}}
+; OPT-NEXT: end_loop{{$}}
+; OPT-NOT: block
+; OPT: return{{$}}
+; OPT-NEXT: .LBB15_5:
+; OPT-NEXT: end_block{{$}}
+; OPT-NOT: block
+; OPT: .LBB15_6:
+; OPT-NEXT: end_block{{$}}
+; OPT-NOT: block
+; OPT: return{{$}}
+define void @test6(i1 %p, i1 %q) {
+entry:
+ br label %header
+
+header:
+ store volatile i32 0, i32* null
+ br i1 %p, label %more, label %second
+
+more:
+ store volatile i32 1, i32* null
+ br i1 %q, label %evenmore, label %first
+
+evenmore:
+ store volatile i32 1, i32* null
+ br i1 %q, label %header, label %return
+
+return:
+ store volatile i32 2, i32* null
+ ret void
+
+first:
+ store volatile i32 3, i32* null
+ br label %second
+
+second:
+ store volatile i32 4, i32* null
+ ret void
+}
+
+; Test a case where there are multiple backedges and multiple loop exits
+; that end in unreachable.
+
+; CHECK-LABEL: test7:
+; CHECK: .LBB16_1:
+; CHECK-NEXT: loop{{$}}
+; CHECK-NOT: block
+; CHECK: block{{$}}
+; CHECK: br_if {{[^,]*}}, 0{{$}}
+; CHECK-NOT: block
+; CHECK: br_if {{[^,]*}}, 1{{$}}
+; CHECK-NOT: block
+; CHECK: unreachable
+; CHECK-NEXT: .LBB16_4:
+; CHECK-NEXT: end_block{{$}}
+; CHECK-NOT: block
+; CHECK: br_if {{[^,]*}}, 0{{$}}
+; CHECK-NEXT: end_loop{{$}}
+; CHECK-NOT: block
+; CHECK: unreachable
+; OPT-LABEL: test7:
+; OPT: .LBB16_1:
+; OPT-NEXT: loop{{$}}
+; OPT-NOT: block
+; OPT: block{{$}}
+; OPT-NOT: block
+; OPT: br_if {{[^,]*}}, 0{{$}}
+; OPT-NOT: block
+; OPT: br_if {{[^,]*}}, 1{{$}}
+; OPT-NOT: block
+; OPT: unreachable
+; OPT-NEXT: .LBB16_4:
+; OPT-NEXT: end_block{{$}}
+; OPT-NOT: block
+; OPT: br_if {{[^,]*}}, 0{{$}}
+; OPT-NEXT: end_loop{{$}}
+; OPT-NOT: block
+; OPT: unreachable
+define void @test7(i1 %tobool2, i1 %tobool9) {
+entry:
+ store volatile i32 0, i32* null
+ br label %loop
+
+loop:
+ store volatile i32 1, i32* null
+ br i1 %tobool2, label %l1, label %l0
+
+l0:
+ store volatile i32 2, i32* null
+ br i1 %tobool9, label %loop, label %u0
+
+l1:
+ store volatile i32 3, i32* null
+ br i1 %tobool9, label %loop, label %u1
+
+u0:
+ store volatile i32 4, i32* null
+ unreachable
+
+u1:
+ store volatile i32 5, i32* null
+ unreachable
+}
+
+; Test an interesting case using nested loops and switches.
+
+; CHECK-LABEL: test8:
+; CHECK: .LBB17_1:
+; CHECK-NEXT: loop{{$}}
+; CHECK-NEXT: block{{$}}
+; CHECK-NOT: block
+; CHECK: br_if {{[^,]*}}, 0{{$}}
+; CHECK-NOT: block
+; CHECK: br_if {{[^,]*}}, 1{{$}}
+; CHECK-NEXT: .LBB17_3:
+; CHECK-NEXT: end_block{{$}}
+; CHECK-NEXT: loop{{$}}
+; CHECK-NEXT: br_if {{[^,]*}}, 0{{$}}
+; CHECK-NEXT: br 2{{$}}
+; CHECK-NEXT: .LBB17_4:
+; OPT-LABEL: test8:
+; OPT: .LBB17_1:
+; OPT-NEXT: loop{{$}}
+; OPT-NEXT: block{{$}}
+; OPT-NOT: block
+; OPT: br_if {{[^,]*}}, 0{{$}}
+; OPT-NOT: block
+; OPT: br_if {{[^,]*}}, 1{{$}}
+; OPT-NEXT: .LBB17_3:
+; OPT-NEXT: end_block{{$}}
+; OPT-NEXT: loop{{$}}
+; OPT-NEXT: br_if {{[^,]*}}, 0{{$}}
+; OPT-NEXT: br 2{{$}}
+; OPT-NEXT: .LBB17_4:
+define i32 @test8() {
+bb:
+ br label %bb1
+
+bb1:
+ br i1 undef, label %bb2, label %bb3
+
+bb2:
+ switch i8 undef, label %bb1 [
+ i8 44, label %bb2
+ ]
+
+bb3:
+ switch i8 undef, label %bb1 [
+ i8 44, label %bb2
+ ]
+}
+
+; Test an interesting case using nested loops that share a bottom block.
+
+; CHECK-LABEL: test9:
+; CHECK: .LBB18_1:
+; CHECK-NEXT: loop{{$}}
+; CHECK-NOT: block
+; CHECK: br_if {{[^,]*}}, 1{{$}}
+; CHECK-NEXT: .LBB18_2:
+; CHECK-NEXT: loop{{$}}
+; CHECK-NOT: block
+; CHECK: block{{$}}
+; CHECK-NOT: block
+; CHECK: br_if {{[^,]*}}, 0{{$}}
+; CHECK-NOT: block
+; CHECK: br_if {{[^,]*}}, 1{{$}}
+; CHECK-NEXT: br 3{{$}}
+; CHECK-NEXT: .LBB18_4:
+; CHECK-NEXT: end_block{{$}}
+; CHECK-NOT: block
+; CHECK: br_if {{[^,]*}}, 0{{$}}
+; CHECK-NEXT: br 2{{$}}
+; CHECK-NEXT: .LBB18_5:
+; CHECK-NOT: block
+; CHECK: return{{$}}
+; OPT-LABEL: test9:
+; OPT: .LBB18_1:
+; OPT-NEXT: loop{{$}}
+; OPT-NOT: block
+; OPT: br_if {{[^,]*}}, 1{{$}}
+; OPT-NEXT: .LBB18_2:
+; OPT-NEXT: loop{{$}}
+; OPT-NOT: block
+; OPT: block{{$}}
+; OPT-NOT: block
+; OPT: br_if {{[^,]*}}, 0{{$}}
+; OPT-NOT: block
+; OPT: br_if {{[^,]*}}, 1{{$}}
+; OPT-NEXT: br 3{{$}}
+; OPT-NEXT: .LBB18_4:
+; OPT-NEXT: end_block{{$}}
+; OPT-NOT: block
+; OPT: br_if {{[^,]*}}, 0{{$}}
+; OPT-NEXT: br 2{{$}}
+; OPT-NEXT: .LBB18_5:
+; OPT-NOT: block
+; OPT: return{{$}}
+declare i1 @a()
+define void @test9() {
+entry:
+ store volatile i32 0, i32* null
+ br label %header
+
+header:
+ store volatile i32 1, i32* null
+ %call4 = call i1 @a()
+ br i1 %call4, label %header2, label %end
+
+header2:
+ store volatile i32 2, i32* null
+ %call = call i1 @a()
+ br i1 %call, label %if.then, label %if.else
+
+if.then:
+ store volatile i32 3, i32* null
+ %call3 = call i1 @a()
+ br i1 %call3, label %header2, label %header
+
+if.else:
+ store volatile i32 4, i32* null
+ %call2 = call i1 @a()
+ br i1 %call2, label %header2, label %header
+
+end:
+ store volatile i32 5, i32* null
+ ret void
+}
+
+; Test an interesting case involving nested loops sharing a loop bottom,
+; and loop exits to a block with unreachable.
+
+; CHECK-LABEL: test10:
+; CHECK: .LBB19_1:
+; CHECK-NEXT: loop{{$}}
+; CHECK-NOT: block
+; CHECK: br_if {{[^,]*}}, 0{{$}}
+; CHECK-NEXT: .LBB19_2:
+; CHECK-NEXT: block{{$}}
+; CHECK-NEXT: loop{{$}}
+; CHECK-NOT: block
+; CHECK: .LBB19_3:
+; CHECK-NEXT: loop{{$}}
+; CHECK-NOT: block
+; CHECK: br_if {{[^,]*}}, 5{{$}}
+; CHECK-NOT: block
+; CHECK: tableswitch {{[^,]*}}, 0, 0, 1, 5, 2, 4{{$}}
+; CHECK-NEXT: .LBB19_5:
+; CHECK-NEXT: end_loop{{$}}
+; CHECK-NEXT: end_loop{{$}}
+; CHECK-NEXT: return{{$}}
+; CHECK-NEXT: .LBB19_6:
+; CHECK-NEXT: end_block{{$}}
+; CHECK-NOT: block
+; CHECK: br 0{{$}}
+; CHECK-NEXT: .LBB19_7:
+; OPT-LABEL: test10:
+; OPT: .LBB19_1:
+; OPT-NEXT: loop{{$}}
+; OPT-NOT: block
+; OPT: br_if {{[^,]*}}, 0{{$}}
+; OPT-NEXT: .LBB19_2:
+; OPT-NEXT: block{{$}}
+; OPT-NEXT: loop{{$}}
+; OPT-NOT: block
+; OPT: .LBB19_3:
+; OPT-NEXT: loop{{$}}
+; OPT-NOT: block
+; OPT: br_if {{[^,]*}}, 5{{$}}
+; OPT-NOT: block
+; OPT: tableswitch {{[^,]*}}, 0, 0, 1, 5, 2, 4{{$}}
+; OPT-NEXT: .LBB19_5:
+; OPT-NEXT: end_loop{{$}}
+; OPT-NEXT: end_loop{{$}}
+; OPT-NEXT: return{{$}}
+; OPT-NEXT: .LBB19_6:
+; OPT-NEXT: end_block{{$}}
+; OPT-NOT: block
+; OPT: br 0{{$}}
+; OPT-NEXT: .LBB19_7:
+define void @test10() {
+bb0:
+ br label %bb1
+
+bb1:
+ %tmp = phi i32 [ 2, %bb0 ], [ 3, %bb3 ]
+ %tmp3 = phi i32 [ undef, %bb0 ], [ %tmp11, %bb3 ]
+ %tmp4 = icmp eq i32 %tmp3, 0
+ br i1 %tmp4, label %bb4, label %bb2
+
+bb2:
+ br label %bb3
+
+bb3:
+ %tmp11 = phi i32 [ 1, %bb5 ], [ 0, %bb2 ]
+ br label %bb1
+
+bb4:
+ %tmp6 = phi i32 [ %tmp9, %bb5 ], [ 4, %bb1 ]
+ %tmp7 = phi i32 [ %tmp6, %bb5 ], [ %tmp, %bb1 ]
+ br label %bb5
+
+bb5:
+ %tmp9 = phi i32 [ %tmp6, %bb5 ], [ %tmp7, %bb4 ]
+ switch i32 %tmp9, label %bb2 [
+ i32 0, label %bb5
+ i32 1, label %bb6
+ i32 3, label %bb4
+ i32 4, label %bb3
+ ]
+
+bb6:
+ ret void
+}
+
+; Test a CFG DAG with interesting merging.
+
+; CHECK-LABEL: test11:
+; CHECK: block{{$}}
+; CHECK-NEXT: block{{$}}
+; CHECK-NEXT: block{{$}}
+; CHECK-NEXT: block{{$}}
+; CHECK-NEXT: br_if {{[^,]*}}, 0{{$}}
+; CHECK-NEXT: block{{$}}
+; CHECK-NOT: block
+; CHECK: br_if {{[^,]*}}, 0{{$}}
+; CHECK-NOT: block
+; CHECK: br_if {{[^,]*}}, 2{{$}}
+; CHECK-NEXT: .LBB20_3:
+; CHECK-NEXT: end_block{{$}}
+; CHECK-NOT: block
+; CHECK: return{{$}}
+; CHECK-NEXT: .LBB20_4:
+; CHECK-NEXT: end_block{{$}}
+; CHECK-NOT: block
+; CHECK: br_if {{[^,]*}}, 2{{$}}
+; CHECK-NOT: block
+; CHECK: br_if {{[^,]*}}, 1{{$}}
+; CHECK-NEXT: .LBB20_6:
+; CHECK-NEXT: end_block{{$}}
+; CHECK-NOT: block
+; CHECK: return{{$}}
+; CHECK-NEXT: .LBB20_7:
+; CHECK-NEXT: end_block{{$}}
+; CHECK-NOT: block
+; CHECK: return{{$}}
+; CHECK-NEXT: .LBB20_8:
+; CHECK-NEXT: end_block{{$}}
+; CHECK-NOT: block
+; CHECK: return{{$}}
+; OPT-LABEL: test11:
+; OPT: block{{$}}
+; OPT-NEXT: block{{$}}
+; OPT-NEXT: br_if $0, 0{{$}}
+; OPT-NEXT: block{{$}}
+; OPT-NOT: block
+; OPT: br_if $0, 0{{$}}
+; OPT-NOT: block
+; OPT: br_if $0, 2{{$}}
+; OPT-NEXT: .LBB20_3:
+; OPT-NEXT: end_block{{$}}
+; OPT-NOT: block
+; OPT: return{{$}}
+; OPT-NEXT: .LBB20_4:
+; OPT-NEXT: end_block{{$}}
+; OPT-NOT: block
+; OPT: block{{$}}
+; OPT-NOT: block
+; OPT: br_if $pop9, 0{{$}}
+; OPT-NOT: block
+; OPT: return{{$}}
+; OPT-NEXT: .LBB20_6:
+; OPT-NEXT: end_block{{$}}
+; OPT-NOT: block
+; OPT: br_if $0, 0{{$}}
+; OPT-NOT: block
+; OPT: return{{$}}
+; OPT-NEXT: .LBB20_8:
+; OPT-NEXT: end_block{{$}}
+; OPT-NOT: block
+; OPT: return{{$}}
+define void @test11() {
+bb0:
+ store volatile i32 0, i32* null
+ br i1 undef, label %bb1, label %bb4
+bb1:
+ store volatile i32 1, i32* null
+ br i1 undef, label %bb3, label %bb2
+bb2:
+ store volatile i32 2, i32* null
+ br i1 undef, label %bb3, label %bb7
+bb3:
+ store volatile i32 3, i32* null
+ ret void
+bb4:
+ store volatile i32 4, i32* null
+ br i1 undef, label %bb8, label %bb5
+bb5:
+ store volatile i32 5, i32* null
+ br i1 undef, label %bb6, label %bb7
+bb6:
+ store volatile i32 6, i32* null
+ ret void
+bb7:
+ store volatile i32 7, i32* null
+ ret void
+bb8:
+ store volatile i32 8, i32* null
+ ret void
+}
+
+; CHECK-LABEL: test12:
+; CHECK: .LBB21_1:
+; CHECK-NEXT: loop{{$}}
+; CHECK-NOT: block
+; CHECK: block{{$}}
+; CHECK-NEXT: block{{$}}
+; CHECK-NEXT: block{{$}}
+; CHECK: br_if {{[^,]*}}, 0{{$}}
+; CHECK-NOT: block
+; CHECK: br_if {{[^,]*}}, 2{{$}}
+; CHECK-NOT: block
+; CHECK: br_if {{[^,]*}}, 2{{$}}
+; CHECK-NEXT: br 1{{$}}
+; CHECK-NEXT: .LBB21_4:
+; CHECK-NEXT: end_block{{$}}
+; CHECK-NOT: block
+; CHECK: br_if {{[^,]*}}, 1{{$}}
+; CHECK-NOT: block
+; CHECK: br_if {{[^,]*}}, 1{{$}}
+; CHECK-NEXT: .LBB21_6:
+; CHECK-NEXT: end_block{{$}}
+; CHECK-NEXT: return{{$}}
+; CHECK-NEXT: .LBB21_7:
+; CHECK-NEXT: end_block{{$}}
+; CHECK-NOT: block
+; CHECK: br 0{{$}}
+; CHECK-NEXT: .LBB21_8:
+; OPT-LABEL: test12:
+; OPT: .LBB21_1:
+; OPT-NEXT: loop{{$}}
+; OPT-NOT: block
+; OPT: block{{$}}
+; OPT-NEXT: block{{$}}
+; OPT-NEXT: block{{$}}
+; OPT: br_if {{[^,]*}}, 0{{$}}
+; OPT-NOT: block
+; OPT: br_if {{[^,]*}}, 2{{$}}
+; OPT-NOT: block
+; OPT: br_if {{[^,]*}}, 2{{$}}
+; OPT-NEXT: br 1{{$}}
+; OPT-NEXT: .LBB21_4:
+; OPT-NEXT: end_block{{$}}
+; OPT-NOT: block
+; OPT: br_if {{[^,]*}}, 1{{$}}
+; OPT-NOT: block
+; OPT: br_if {{[^,]*}}, 1{{$}}
+; OPT-NEXT: .LBB21_6:
+; OPT-NEXT: end_block{{$}}
+; OPT-NEXT: return{{$}}
+; OPT-NEXT: .LBB21_7:
+; OPT-NEXT: end_block{{$}}
+; OPT-NOT: block
+; OPT: br 0{{$}}
+; OPT-NEXT: .LBB21_8:
+define void @test12(i8* %arg) {
+bb:
+ br label %bb1
+
+bb1:
+ %tmp = phi i32 [ 0, %bb ], [ %tmp5, %bb4 ]
+ %tmp2 = getelementptr i8, i8* %arg, i32 %tmp
+ %tmp3 = load i8, i8* %tmp2
+ switch i8 %tmp3, label %bb7 [
+ i8 42, label %bb4
+ i8 76, label %bb4
+ i8 108, label %bb4
+ i8 104, label %bb4
+ ]
+
+bb4:
+ %tmp5 = add i32 %tmp, 1
+ br label %bb1
+
+bb7:
+ ret void
+}
+
+; A block can be "branched to" from another even if it is also reachable via
+; fallthrough from the other. This would normally be optimized away, so use
+; optnone to disable optimizations to test this case.
+
+; CHECK-LABEL: test13:
+; CHECK-NEXT: local i32{{$}}
+; CHECK: block{{$}}
+; CHECK: br_if $pop4, 0{{$}}
+; CHECK-NEXT: return{{$}}
+; CHECK-NEXT: .LBB22_2:
+; CHECK-NEXT: end_block{{$}}
+; CHECK: block{{$}}
+; CHECK-NEXT: br_if $0, 0{{$}}
+; CHECK: .LBB22_4:
+; CHECK-NEXT: end_block{{$}}
+; CHECK: block{{$}}
+; CHECK: br_if $pop6, 0{{$}}
+; CHECK-NEXT: end_block{{$}}
+; CHECK-NEXT: unreachable{{$}}
+; OPT-LABEL: test13:
+; OPT-NEXT: local i32{{$}}
+; OPT: block{{$}}
+; OPT: br_if $pop4, 0{{$}}
+; OPT-NEXT: return{{$}}
+; OPT-NEXT: .LBB22_2:
+; OPT-NEXT: end_block{{$}}
+; OPT: block{{$}}
+; OPT-NEXT: br_if $0, 0{{$}}
+; OPT: .LBB22_4:
+; OPT-NEXT: end_block{{$}}
+; OPT: block{{$}}
+; OPT: br_if $pop6, 0{{$}}
+; OPT-NEXT: end_block{{$}}
+; OPT-NEXT: unreachable{{$}}
+define void @test13() noinline optnone {
+bb:
+ br i1 undef, label %bb5, label %bb2
+bb1:
+ unreachable
+bb2:
+ br i1 undef, label %bb3, label %bb4
+bb3:
+ br label %bb4
+bb4:
+ %tmp = phi i1 [ false, %bb2 ], [ false, %bb3 ]
+ br i1 %tmp, label %bb1, label %bb1
+bb5:
+ ret void
+}
+
+; Test a case with a single-block loop that has another loop
+; as a successor. The end_loop for the first loop should go
+; before the loop for the second.
+
+; CHECK-LABEL: test14:
+; CHECK-NEXT: local i32{{$}}
+; CHECK-NEXT: i32.const $0=, 0{{$}}
+; CHECK-NEXT: .LBB23_1:{{$}}
+; CHECK-NEXT: loop{{$}}
+; CHECK-NEXT: br_if $0, 0{{$}}
+; CHECK-NEXT: .LBB23_2:{{$}}
+; CHECK-NEXT: end_loop{{$}}
+; CHECK-NEXT: loop{{$}}
+; CHECK-NEXT: br_if $0, 0{{$}}
+; CHECK-NEXT: end_loop{{$}}
+; CHECK-NEXT: return{{$}}
+define void @test14() {
+bb:
+ br label %bb1
+
+bb1:
+ %tmp = bitcast i1 undef to i1
+ br i1 %tmp, label %bb3, label %bb1
+
+bb3:
+ br label %bb4
+
+bb4:
+ br i1 undef, label %bb7, label %bb48
+
+bb7:
+ br i1 undef, label %bb12, label %bb12
+
+bb12:
+ br i1 undef, label %bb17, label %bb17
+
+bb17:
+ br i1 undef, label %bb22, label %bb22
+
+bb22:
+ br i1 undef, label %bb27, label %bb27
+
+bb27:
+ br i1 undef, label %bb30, label %bb30
+
+bb30:
+ br i1 undef, label %bb35, label %bb35
+
+bb35:
+ br i1 undef, label %bb38, label %bb38
+
+bb38:
+ br i1 undef, label %bb48, label %bb48
+
+bb48:
+ %tmp49 = bitcast i1 undef to i1
+ br i1 %tmp49, label %bb3, label %bb50
+
+bb50:
+ ret void
+}