+; RUN: opt < %s -S -early-cse | FileCheck %s
+
+; CHECK-LABEL: @test12(
+define i32 @test12(i1 %B, i32* %P1, i32* %P2) {
+ %load0 = load i32, i32* %P1
+ %1 = load atomic i32, i32* %P2 seq_cst, align 4
+ %load1 = load i32, i32* %P1
+ %sel = select i1 %B, i32 %load0, i32 %load1
+ ret i32 %sel
+ ; CHECK: load i32, i32* %P1
+ ; CHECK: load i32, i32* %P1
+}
+
+; CHECK-LABEL: @test13(
+; atomic to non-atomic forwarding is legal
+define i32 @test13(i1 %B, i32* %P1) {
+ %a = load atomic i32, i32* %P1 seq_cst, align 4
+ %b = load i32, i32* %P1
+ %res = sub i32 %a, %b
+ ret i32 %res
+ ; CHECK: load atomic i32, i32* %P1
+ ; CHECK: ret i32 0
+}
+
+; CHECK-LABEL: @test14(
+; atomic to unordered atomic forwarding is legal
+define i32 @test14(i1 %B, i32* %P1) {
+ %a = load atomic i32, i32* %P1 seq_cst, align 4
+ %b = load atomic i32, i32* %P1 unordered, align 4
+ %res = sub i32 %a, %b
+ ret i32 %res
+ ; CHECK: load atomic i32, i32* %P1
+ ; CHECK: ret i32 0
+}
+
+; CHECK-LABEL: @test15(
+; implementation restiction: can't forward to stonger
+; than unordered
+define i32 @test15(i1 %B, i32* %P1, i32* %P2) {
+ %a = load atomic i32, i32* %P1 seq_cst, align 4
+ %b = load atomic i32, i32* %P1 seq_cst, align 4
+ %res = sub i32 %a, %b
+ ret i32 %res
+ ; CHECK: load atomic i32, i32* %P1
+ ; CHECK: load atomic i32, i32* %P1
+}
+
+; CHECK-LABEL: @test16(
+; forwarding non-atomic to atomic is wrong! (However,
+; it would be legal to use the later value in place of the
+; former in this particular example. We just don't
+; do that right now.)
+define i32 @test16(i1 %B, i32* %P1, i32* %P2) {
+ %a = load i32, i32* %P1, align 4
+ %b = load atomic i32, i32* %P1 unordered, align 4
+ %res = sub i32 %a, %b
+ ret i32 %res
+ ; CHECK: load i32, i32* %P1
+ ; CHECK: load atomic i32, i32* %P1
+}
+
+; Can't DSE across a full fence
+define void @test17(i1 %B, i32* %P1, i32* %P2) {
+; CHECK-LABEL: @test17
+; CHECK: store
+; CHECK: store atomic
+; CHECK: store
+ store i32 0, i32* %P1, align 4
+ store atomic i32 0, i32* %P2 seq_cst, align 4
+ store i32 0, i32* %P1, align 4
+ ret void
+}
+
+; Can't remove a volatile load
+define i32 @test18(i1 %B, i32* %P1, i32* %P2) {
+ %a = load i32, i32* %P1, align 4
+ %b = load volatile i32, i32* %P1, align 4
+ %res = sub i32 %a, %b
+ ret i32 %res
+ ; CHECK-LABEL: @test18
+ ; CHECK: load i32, i32* %P1
+ ; CHECK: load volatile i32, i32* %P1
+}
+
+; Can't DSE a volatile store
+define void @test19(i1 %B, i32* %P1, i32* %P2) {
+; CHECK-LABEL: @test19
+; CHECK: store volatile
+; CHECK: store
+ store volatile i32 0, i32* %P1, align 4
+ store i32 3, i32* %P1, align 4
+ ret void
+}
+
+; Can value forward from volailes
+define i32 @test20(i1 %B, i32* %P1, i32* %P2) {
+ %a = load volatile i32, i32* %P1, align 4
+ %b = load i32, i32* %P1, align 4
+ %res = sub i32 %a, %b
+ ret i32 %res
+ ; CHECK-LABEL: @test20
+ ; CHECK: load volatile i32, i32* %P1
+ ; CHECK: ret i32 0
+}
+
+; Can DSE a non-volatile store in favor of a volatile one
+; currently a missed optimization
+define void @test21(i1 %B, i32* %P1, i32* %P2) {
+; CHECK-LABEL: @test21
+; CHECK: store
+; CHECK: store volatile
+ store i32 0, i32* %P1, align 4
+ store volatile i32 3, i32* %P1, align 4
+ ret void
+}
+
+; Can DSE a normal store in favor of a unordered one
+define void @test22(i1 %B, i32* %P1, i32* %P2) {
+; CHECK-LABEL: @test22
+; CHECK-NEXT: store atomic
+ store i32 0, i32* %P1, align 4
+ store atomic i32 3, i32* %P1 unordered, align 4
+ ret void
+}
+
+
+