From b846719663fb7f7847dacf956696ef257ab88d8e Mon Sep 17 00:00:00 2001 From: Bill Wendling Date: Tue, 23 Oct 2012 18:37:11 +0000 Subject: Ignore unreachable blocks when doing memory dependence analysis on non-local loads. It's not really profitable and may result in GVN going into an infinite loop when it hits constructs like this: %x = gep %some.type %x, ... Found via an LTO build of LLVM. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166490 91177308-0d34-0410-b5e6-96231b3b80d8 --- test/Transforms/GVN/crash.ll | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) (limited to 'test') diff --git a/test/Transforms/GVN/crash.ll b/test/Transforms/GVN/crash.ll index 31eae256c6..4a8c8e4589 100644 --- a/test/Transforms/GVN/crash.ll +++ b/test/Transforms/GVN/crash.ll @@ -163,3 +163,39 @@ entry: ret i8 %1 } + +; Test that a GEP in an unreachable block with the following form doesn't crash +; GVN: +; +; %x = gep %some.type %x, ... + +%struct.type = type { i64, i32, i32 } + +define fastcc void @func() nounwind uwtable ssp align 2 { +entry: + br label %reachable.bb + +;; Unreachable code. + +unreachable.bb: + %gep.val = getelementptr inbounds %struct.type* %gep.val, i64 1 + br i1 undef, label %u2.bb, label %u1.bb + +u1.bb: + %tmp1 = getelementptr inbounds %struct.type* %gep.val, i64 0, i32 0 + store i64 -1, i64* %tmp1, align 8 + br label %unreachable.bb + +u2.bb: + %0 = load i32* undef, align 4 + %conv.i.i.i.i.i = zext i32 %0 to i64 + br label %u2.bb + +;; Reachable code. + +reachable.bb: + br label %r1.bb + +r1.bb: + br label %u2.bb +} -- cgit v1.2.3