[PATCH] D155626: [DAG][AArch64] Fix truncated vscale constant types

Dave Green via Phabricator via llvm-commits llvm-commits at lists.llvm.org
Tue Jul 18 13:18:12 PDT 2023


dmgreen updated this revision to Diff 541699.
dmgreen added a comment.

Just trunc the constant, as opposed to being opinionated about the sign.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D155626/new/

https://reviews.llvm.org/D155626

Files:
  llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
  llvm/test/CodeGen/AArch64/sve-vscale.ll


Index: llvm/test/CodeGen/AArch64/sve-vscale.ll
===================================================================
--- llvm/test/CodeGen/AArch64/sve-vscale.ll
+++ llvm/test/CodeGen/AArch64/sve-vscale.ll
@@ -101,6 +101,17 @@
   ret i32 %1
 }
 
+define i1 @rdvl_i1() {
+; CHECK-LABEL: rdvl_i1:
+; CHECK:         rdvl x8, #-1
+; CHECK-NEXT:    asr x8, x8, #4
+; CHECK-NEXT:    and w0, w8, #0x1
+; CHECK-NEXT:    ret
+  %a = tail call i64 @llvm.vscale.i64()
+  %b = trunc i64 %a to i1
+  ret i1 %b
+}
+
 ;
 ; CNTH
 ;
Index: llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
===================================================================
--- llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -5751,7 +5751,9 @@
     if (OpOpcode == ISD::UNDEF)
       return getUNDEF(VT);
     if (OpOpcode == ISD::VSCALE && !NewNodesMustHaveLegalTypes)
-      return getVScale(DL, VT, N1.getConstantOperandAPInt(0));
+      return getVScale(
+          DL, VT,
+          N1.getConstantOperandAPInt(0).trunc(VT.getScalarSizeInBits()));
     break;
   case ISD::ANY_EXTEND_VECTOR_INREG:
   case ISD::ZERO_EXTEND_VECTOR_INREG:


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