return false;
return LI->getPointerOperand()->isDereferenceablePointer();
}
- case Instruction::Call:
+ case Instruction::Call: {
+ if (const IntrinsicInst *II = dyn_cast<IntrinsicInst>(Inst)) {
+ switch (II->getIntrinsicID()) {
+ case Intrinsic::bswap:
+ case Intrinsic::ctlz:
+ case Intrinsic::ctpop:
+ case Intrinsic::cttz:
+ case Intrinsic::objectsize:
+ case Intrinsic::sadd_with_overflow:
+ case Intrinsic::smul_with_overflow:
+ case Intrinsic::ssub_with_overflow:
+ case Intrinsic::uadd_with_overflow:
+ case Intrinsic::umul_with_overflow:
+ case Intrinsic::usub_with_overflow:
+ return true;
+ // TODO: some fp intrinsics are marked as having the same error handling
+ // as libm. They're safe to speculate when they won't error.
+ // TODO: are convert_{from,to}_fp16 safe?
+ // TODO: can we list target-specific intrinsics here?
+ default: break;
+ }
+ }
return false; // The called function could have undefined behavior or
- // side-effects.
- // FIXME: We should special-case some intrinsics (bswap,
- // overflow-checking arithmetic, etc.)
+ // side-effects, even if marked readnone nounwind.
+ }
case Instruction::VAArg:
case Instruction::Alloca:
case Instruction::Invoke:
-; RUN: opt < %s -simplifycfg -S | grep select
-; RUN: opt < %s -simplifycfg -S | grep br | count 2
+; RUN: opt < %s -simplifycfg -phi-node-folding-threshold=2 -S | FileCheck %s
-define i32 @t2(i32 %a, i32 %b, i32 %c) nounwind {
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @test1(i32 %a, i32 %b, i32 %c) nounwind {
+; CHECK: @test1
entry:
%tmp1 = icmp eq i32 %b, 0
br i1 %tmp1, label %bb1, label %bb3
bb1: ; preds = %entry
%tmp2 = icmp sgt i32 %c, 1
br i1 %tmp2, label %bb2, label %bb3
+; CHECK: bb1:
+; CHECK-NEXT: add i32 %a, 1
+; CHECK-NEXT: icmp sgt i32 %c, 1
+; CHECK-NEXT: select i1 %tmp2, i32 %tmp3, i32 %a
+; CHECK-NEXT: br label %bb3
bb2: ; preds = bb1
%tmp3 = add i32 %a, 1
%tmp5 = sub i32 %tmp4, 1
ret i32 %tmp5
}
+
+declare i8 @llvm.cttz.i8(i8, i1)
+
+define i8 @test2(i8 %a) {
+; CHECK: @test2
+ br i1 undef, label %bb_true, label %bb_false
+bb_true:
+ %b = tail call i8 @llvm.cttz.i8(i8 %a, i1 false)
+ br label %join
+bb_false:
+ br label %join
+join:
+ %c = phi i8 [%b, %bb_true], [%a, %bb_false]
+; CHECK: select
+ ret i8 %c
+}
+