Disabling r312514 as it causes miscompiles that show up on bootstrap

The compare elimination peephole introduced in https://reviews.llvm.org/rL312514
causes a miscompile in AMDGPUInstrInfo.cpp which in turn causes some AMDGPU
test case failures in stage2 bootstrap testing. This miscompile didn't cause any
test case failures until https://reviews.llvm.org/rL320614, so it appeared as if
that patch caused these failures.
Disabling this transformation for now to bring the build bots back to green and
the author of the patch will investigate the miscompile.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@320786 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/PowerPC/PPCMIPeephole.cpp b/lib/Target/PowerPC/PPCMIPeephole.cpp
index 05eb7563893da80092621d013fd4d680ed927cea..2f44b8c13a36c5a9b5982c56dec4e1f0e589dca0 100644 (file)
--- a/lib/Target/PowerPC/PPCMIPeephole.cpp
+++ b/lib/Target/PowerPC/PPCMIPeephole.cpp
@@ -729,7 +729,7 @@ bool PPCMIPeephole::simplifyCode(void) {
   // Eliminate all the TOC save instructions which are redundant.
   Simplified |= eliminateRedundantTOCSaves(TOCSaves);
   // We try to eliminate redundant compare instruction.
-  Simplified |= eliminateRedundantCompare();
+  //Simplified |= eliminateRedundantCompare();
 
   return Simplified;
 }

diff --git a/test/CodeGen/PowerPC/cmp_elimination.ll b/test/CodeGen/PowerPC/cmp_elimination.ll
index 4839520039acf5e5fe6a3daea6196d704a94ebde..3251ae2881b93681ba0728b3fb74d0f9f42726ea 100644 (file)
--- a/test/CodeGen/PowerPC/cmp_elimination.ll
+++ b/test/CodeGen/PowerPC/cmp_elimination.ll
@@ -1,3 +1,4 @@
+; XFAIL: *
 ; RUN: llc -verify-machineinstrs < %s -mtriple=powerpc64-unknown-linux-gnu | FileCheck %s
 ; RUN: llc -verify-machineinstrs < %s -mtriple=powerpc64le-unknown-linux-gnu | FileCheck %s