From 02bf98ab38355aafbe9a763caa019bc06ad9ce3d Mon Sep 17 00:00:00 2001 From: Chandler Carruth Date: Wed, 17 Oct 2012 09:23:48 +0000 Subject: This just in, it is a *bad idea* to use 'udiv' on an offset of a pointer. A very bad idea. Let's not do that. Fixes PR14105. Note that this wasn't *that* glaring of an oversight. Originally, these routines were only called on offsets within an alloca, which are intrinsically positive. But over the evolution of the pass, they ended up being called for arbitrary offsets, and things went downhill... git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166095 91177308-0d34-0410-b5e6-96231b3b80d8 --- test/Transforms/SROA/basictest.ll | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) (limited to 'test') diff --git a/test/Transforms/SROA/basictest.ll b/test/Transforms/SROA/basictest.ll index 644fda167d..03120f7a32 100644 --- a/test/Transforms/SROA/basictest.ll +++ b/test/Transforms/SROA/basictest.ll @@ -1063,3 +1063,23 @@ entry: call void @llvm.lifetime.end(i64 -1, i8* %0) ret void } + +define void @PR14105({ [16 x i8] }* %ptr) { +; Ensure that when rewriting the GEP index '-1' for this alloca we preserve is +; sign as negative. We use a volatile memcpy to ensure promotion never actually +; occurs. +; CHECK: @PR14105 + +entry: + %a = alloca { [16 x i8] }, align 8 +; CHECK: alloca [16 x i8], align 8 + + %gep = getelementptr inbounds { [16 x i8] }* %ptr, i64 -1 +; CHECK-NEXT: getelementptr inbounds { [16 x i8] }* %ptr, i64 -1, i32 0, i64 0 + + %cast1 = bitcast { [16 x i8 ] }* %gep to i8* + %cast2 = bitcast { [16 x i8 ] }* %a to i8* + call void @llvm.memcpy.p0i8.p0i8.i32(i8* %cast1, i8* %cast2, i32 16, i32 8, i1 true) + ret void +; CHECK: ret +} -- cgit v1.2.3