From 760dc9aba76ad48d74e6015b88da43b8c8e27674 Mon Sep 17 00:00:00 2001 From: Mikael Holmen Date: Wed, 1 Mar 2017 06:45:20 +0000 Subject: Remove sometimes faulty rewrite of memcpy in instcombine. Summary: Solves PR 31990. The bad rewrite could replace a memcpy of one word with store i4 -1 while it should actually be store i8 -1 Hopefully opt and llc has improved enough so the original optimization done by the code isn't needed anymore. One already existing testcase is affected. It originally tested that the memcpy was replaced with load double but since we now remove that rewrite it will be load i64 instead. Patch suggestion by Eli Friedman. Reviewers: eli.friedman, majnemer, efriedma Reviewed By: efriedma Subscribers: efriedma, llvm-commits Differential Revision: https://reviews.llvm.org/D30254 llvm-svn: 296585 --- llvm/test/Transforms/InstCombine/memcpy-to-load.ll | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'llvm/test/Transforms/InstCombine/memcpy-to-load.ll') diff --git a/llvm/test/Transforms/InstCombine/memcpy-to-load.ll b/llvm/test/Transforms/InstCombine/memcpy-to-load.ll index bcc9e188b96..fe5f0ac657f 100644 --- a/llvm/test/Transforms/InstCombine/memcpy-to-load.ll +++ b/llvm/test/Transforms/InstCombine/memcpy-to-load.ll @@ -1,4 +1,4 @@ -; RUN: opt < %s -instcombine -S | grep "load double" +; RUN: opt < %s -instcombine -S | FileCheck %s target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128" target triple = "i686-apple-darwin8" @@ -10,4 +10,8 @@ entry: ret void } +; Make sure that the memcpy has been replace with a load/store of i64 +; CHECK: [[TMP:%[0-9]+]] = load i64 +; CHECK: store i64 [[TMP]] + declare void @llvm.memcpy.p0i8.p0i8.i32(i8* nocapture, i8* nocapture, i32, i32, i1) nounwind -- cgit v1.2.3