From e5742464895b7f1fcc6a5b968b72f6ec66a1fd44 Mon Sep 17 00:00:00 2001 From: Benjamin Kramer Date: Thu, 24 Jan 2013 16:28:28 +0000 Subject: ConstantFolding: Add a missing folding that leads to a miscompile. We use constant folding to see if an intrinsic evaluates to the same value as a constant that we know. If we don't take the undefinedness into account we get a value that doesn't match the actual implementation, and miscompiled code. This was uncovered by Chandler's simplifycfg changes. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@173356 91177308-0d34-0410-b5e6-96231b3b80d8 --- test/Transforms/InstCombine/intrinsics.ll | 36 +++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) (limited to 'test/Transforms/InstCombine/intrinsics.ll') diff --git a/test/Transforms/InstCombine/intrinsics.ll b/test/Transforms/InstCombine/intrinsics.ll index 93f0a953fd..f334b3b1e9 100644 --- a/test/Transforms/InstCombine/intrinsics.ll +++ b/test/Transforms/InstCombine/intrinsics.ll @@ -220,3 +220,39 @@ define i32 @cttz_simplify1b(i32 %x) nounwind readnone ssp { ; CHECK: @cttz_simplify1b ; CHECK-NEXT: ret i32 0 } + +define i32 @ctlz_undef(i32 %Value) nounwind { + %ctlz = call i32 @llvm.ctlz.i32(i32 0, i1 true) + ret i32 %ctlz + +; CHECK: @ctlz_undef +; CHECK-NEXT: ret i32 undef +} + +define i32 @cttz_undef(i32 %Value) nounwind { + %cttz = call i32 @llvm.cttz.i32(i32 0, i1 true) + ret i32 %cttz + +; CHECK: @cttz_undef +; CHECK-NEXT: ret i32 undef +} + +define i32 @ctlz_select(i32 %Value) nounwind { + %tobool = icmp ne i32 %Value, 0 + %ctlz = call i32 @llvm.ctlz.i32(i32 %Value, i1 true) + %s = select i1 %tobool, i32 %ctlz, i32 32 + ret i32 %s + +; CHECK: @ctlz_select +; CHECK: select i1 %tobool, i32 %ctlz, i32 32 +} + +define i32 @cttz_select(i32 %Value) nounwind { + %tobool = icmp ne i32 %Value, 0 + %cttz = call i32 @llvm.cttz.i32(i32 %Value, i1 true) + %s = select i1 %tobool, i32 %cttz, i32 32 + ret i32 %s + +; CHECK: @cttz_select +; CHECK: select i1 %tobool, i32 %cttz, i32 32 +} -- cgit v1.2.3