commit 821bcba00d5c22c4a829323f8920e0f2dfc1d665
author Yingwei Zheng <dtcxzyw2333@gmail.com> Wed May 22 23:35:37 2024 +0800
committer GitHub <noreply@github.com> Wed May 22 23:35:37 2024 +0800
tree e6f4d39f958a1e4b1d185a48f00d826d810609ed
parent 3c67c227f2e16accd3cdb3aeb4c845edabd2f6c4

[GISel] Add narrowScalar/widenScalar support for `G_CONSTANT_FOLD_BARRIER` (#93031)

Fixes an error that llc fails to legalize `G_CONSTANT_FOLD_BARRIER` with
i16/i128: https://godbolt.org/z/f9n6xM3sv

llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp

diff --git a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
index 4050784..d8b0f52 100644
--- a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
@@ -1296,7 +1296,7 @@
     MI.eraseFromParent();
     return Legalized;
   }
-
+  case TargetOpcode::G_CONSTANT_FOLD_BARRIER:
   case TargetOpcode::G_FREEZE: {
     if (TypeIdx != 0)
       return UnableToLegalize;
@@ -1310,7 +1310,8 @@
     SmallVector<Register, 8> Parts;
     for (unsigned i = 0; i < Unmerge->getNumDefs(); ++i) {
       Parts.push_back(
-          MIRBuilder.buildFreeze(NarrowTy, Unmerge.getReg(i)).getReg(0));
+          MIRBuilder.buildInstr(MI.getOpcode(), {NarrowTy}, {Unmerge.getReg(i)})
+              .getReg(0));
     }
 
     MIRBuilder.buildMergeLikeInstr(MI.getOperand(0).getReg(), Parts);
@@ -2515,6 +2516,7 @@
     return Legalized;
   }
   case TargetOpcode::G_FREEZE:
+  case TargetOpcode::G_CONSTANT_FOLD_BARRIER:
     Observer.changingInstr(MI);
     widenScalarSrc(MI, WideTy, 1, TargetOpcode::G_ANYEXT);
     widenScalarDst(MI, WideTy);