[PATCH] D72853: [GlobalISel] Don't arbitrarily limit a mask to 64 bits

[Jay Foad via Phabricator via llvm-commits]

foad created this revision.
foad added a reviewer: arsenm.
Herald added subscribers: Petar.Avramovic, volkan, hiraditya, rovka, wdng.
Herald added a project: LLVM.

Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D72853

Files:
  llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp


Index: llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
===================================================================
--- llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
+++ llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
@@ -1436,9 +1436,10 @@
     // Do the arithmetic in the larger type.
     auto NewOp = MIRBuilder.buildInstr(Opcode, {WideTy}, {LHSZext, RHSZext});
     LLT OrigTy = MRI.getType(MI.getOperand(0).getReg());
-    APInt Mask = APInt::getAllOnesValue(OrigTy.getSizeInBits());
+    APInt Mask =
+        APInt::getLowBitsSet(WideTy.getSizeInBits(), OrigTy.getSizeInBits());
     auto AndOp = MIRBuilder.buildAnd(
-        WideTy, NewOp, MIRBuilder.buildConstant(WideTy, Mask.getZExtValue()));
+        WideTy, NewOp, MIRBuilder.buildConstant(WideTy, Mask));
     // There is no overflow if the AndOp is the same as NewOp.
     MIRBuilder.buildICmp(CmpInst::ICMP_NE, MI.getOperand(1).getReg(), NewOp,
                          AndOp);


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