From: Jessica Paquette <jpaquette@apple.com>
Date: Wed, 24 Feb 2021 00:12:56 +0000 (-0800)
Subject: [AArch64][GlobalISel] Correct function evaluation order in applyINS
X-Git-Tag: llvmorg-14-init~14230
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=daf7d7f0dc283873f40f3500b20f02bc2cde701d;p=platform%2Fupstream%2Fllvm.git

[AArch64][GlobalISel] Correct function evaluation order in applyINS

The order in which the nested calls to Builder.buildWhatever are
evaluated in differs between GCC and Clang.

This caused a bot failure because the MIR in the testcase was
coming out in a different order than expected.

Rather than using nested calls, pull them out in order to fix the
order of evaluation.
---

diff --git a/llvm/lib/Target/AArch64/GISel/AArch64PostLegalizerLowering.cpp b/llvm/lib/Target/AArch64/GISel/AArch64PostLegalizerLowering.cpp
index 1eba655..3e05983 100644
--- a/llvm/lib/Target/AArch64/GISel/AArch64PostLegalizerLowering.cpp
+++ b/llvm/lib/Target/AArch64/GISel/AArch64PostLegalizerLowering.cpp
@@ -456,11 +456,10 @@ static bool applyINS(MachineInstr &MI, MachineRegisterInfo &MRI,
   Register DstVec, SrcVec;
   int DstLane, SrcLane;
   std::tie(DstVec, DstLane, SrcVec, SrcLane) = MatchInfo;
-  Builder.buildInsertVectorElement(
-      Dst, DstVec,
-      Builder.buildExtractVectorElement(
-          ScalarTy, SrcVec, Builder.buildConstant(LLT::scalar(64), SrcLane)),
-      Builder.buildConstant(LLT::scalar(64), DstLane));
+  auto SrcCst = Builder.buildConstant(LLT::scalar(64), SrcLane);
+  auto Extract = Builder.buildExtractVectorElement(ScalarTy, SrcVec, SrcCst);
+  auto DstCst = Builder.buildConstant(LLT::scalar(64), DstLane);
+  Builder.buildInsertVectorElement(Dst, DstVec, Extract, DstCst);
   MI.eraseFromParent();
   return true;
 }