[PATCH] D67898: [SDAG] Peek through bitcasts before commuting setcc operands

[Pengfei Wang via Phabricator via llvm-commits]

pengfei updated this revision to Diff 221245.
pengfei added a comment.

Add testcase. Thanks @xbolva00


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D67898/new/

https://reviews.llvm.org/D67898

Files:
  llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
  llvm/test/CodeGen/X86/i686-setcc-commute.ll


Index: llvm/test/CodeGen/X86/i686-setcc-commute.ll
===================================================================
--- /dev/null
+++ llvm/test/CodeGen/X86/i686-setcc-commute.ll
@@ -0,0 +1,17 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc < %s -mtriple=i686 -mattr=+avx512f -mattr=avx512vl | FileCheck %s
+
+define <2 x i64> @test(<2 x i64> %a) {
+; CHECK-LABEL: test:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    vpxor %xmm1, %xmm1, %xmm1
+; CHECK-NEXT:    vpsubq %xmm0, %xmm1, %xmm1
+; CHECK-NEXT:    vptestnmq %xmm0, %xmm0, %k1
+; CHECK-NEXT:    vmovdqa64 %xmm0, %xmm1 {%k1}
+; CHECK-NEXT:    vmovdqa %xmm1, %xmm0
+; CHECK-NEXT:    retl
+  %1 = sub <2 x i64> zeroinitializer, %a
+  %2 = icmp eq <2 x i64> %a, zeroinitializer
+  %3 = select <2 x i1> %2, <2 x i64> %a, <2 x i64> %1
+  ret <2 x i64> %3
+}
Index: llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
===================================================================
--- llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
+++ llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
@@ -3069,7 +3069,8 @@
   // -- but in reverse order -- then try to commute the operands of this setcc
   // to match. A matching pair of setcc (cmp) and sub may be combined into 1
   // instruction on some targets.
-  if (!isConstOrConstSplat(N0) && !isConstOrConstSplat(N1) &&
+  if (!isConstOrConstSplat(peekThroughBitcasts(N0)) &&
+      !isConstOrConstSplat(peekThroughBitcasts(N1)) &&
       (DCI.isBeforeLegalizeOps() ||
        isCondCodeLegal(SwappedCC, N0.getSimpleValueType())) &&
       DAG.getNodeIfExists(ISD::SUB, DAG.getVTList(OpVT), { N1, N0 } ) &&


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