From 0a0fa7cf7868c4916deda296a4fd18f997bcbfa6 Mon Sep 17 00:00:00 2001 From: Dan Gohman Date: Thu, 15 May 2008 23:26:57 +0000 Subject: Fix a bug in LoopStrengthReduce that caused it to emit IR with use-before-def. The problem comes up in code with multiple PHIs where one PHI is being rewritten in terms of the other, but the other needs to be casted first. LLVM rules requre the cast instruction to be inserted after any PHI instructions, but when instructions were inserted to replace the second PHI value with a function of the first, they were ended up going before the cast instruction. Avoid this problem by remembering the location of the cast instruction, when one is needed, and inserting the expansion of the new value after it. This fixes a bug that surfaced in 255.vortex on x86-64 when instcombine was removed from the middle of the loop optimization passes. llvm-svn: 51169 --- llvm/test/CodeGen/X86/vortex-bug.ll | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) create mode 100644 llvm/test/CodeGen/X86/vortex-bug.ll (limited to 'llvm/test/CodeGen/X86/vortex-bug.ll') diff --git a/llvm/test/CodeGen/X86/vortex-bug.ll b/llvm/test/CodeGen/X86/vortex-bug.ll new file mode 100644 index 00000000000..680bfbdb349 --- /dev/null +++ b/llvm/test/CodeGen/X86/vortex-bug.ll @@ -0,0 +1,21 @@ +; RUN: llvm-as < %s | llc -march=x86 + + %struct.blktkntype = type { i32, i32 } + %struct.fieldstruc = type { [128 x i8], %struct.blktkntype*, i32, i32 } + +define fastcc i32 @Env_GetFieldStruc(i8* %FieldName, i32* %Status, %struct.fieldstruc* %FieldStruc) nounwind { +entry: + br label %bb137.i + +bb137.i: ; preds = %bb137.i, %entry + %FieldName_addr.0209.rec.i = phi i64 [ %tmp139.rec.i, %bb137.i ], [ 0, %entry ] ; [#uses=1] + %tmp147213.i = phi i32 [ %tmp147.i, %bb137.i ], [ 1, %entry ] ; [#uses=2] + %tmp139.rec.i = add i64 %FieldName_addr.0209.rec.i, 1 ; [#uses=2] + %tmp141142.i = sext i32 %tmp147213.i to i64 ; [#uses=0] + %tmp147.i = add i32 %tmp147213.i, 1 ; [#uses=1] + br i1 false, label %bb137.i, label %bb149.i.loopexit + +bb149.i.loopexit: ; preds = %bb137.i + %tmp139.i = getelementptr i8* %FieldName, i64 %tmp139.rec.i ; [#uses=0] + unreachable +} -- cgit v1.2.3