[PATCH] D107692: [DAGCombine] Prevent the transform of combine for multi-use operand

[Allen zhong via Phabricator via llvm-commits]

Allen updated this revision to Diff 365067.

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D107692/new/

https://reviews.llvm.org/D107692

Files:
  llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
  llvm/test/CodeGen/AArch64/arm64-srl-and.ll


Index: llvm/test/CodeGen/AArch64/arm64-srl-and.ll
===================================================================
--- /dev/null
+++ llvm/test/CodeGen/AArch64/arm64-srl-and.ll
@@ -0,0 +1,29 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -mtriple=aarch64-linux-gnu -O3 < %s | FileCheck %s
+
+; Disable the dagcombine if operand has multi use
+
+ at g = dso_local local_unnamed_addr global i16 0, align 4
+define dso_local noundef i32 @srl_and() local_unnamed_addr  {
+; CHECK-LABEL: srl_and:
+; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    adrp x8, g
+; CHECK-NEXT:    ldrh w8, [x8, :lo12:g]
+; CHECK-NEXT:    mov w9, #50
+; CHECK-NEXT:    eor w8, w8, w9
+; CHECK-NEXT:    mov w9, #65535
+; CHECK-NEXT:    add w8, w8, w9
+; CHECK-NEXT:    and w0, w8, w8, lsr #16
+; CHECK-NEXT:    ret
+entry:
+  %0 = load i16, i16* @g, align 4
+  %1 = xor i16 %0, 50
+  %tobool = icmp ne i16 %1, 0
+  %lor.ext = zext i1 %tobool to i32
+  %sub = add i16 %1, -1
+
+  %srl = zext i16 %sub to i32
+  %and = and i32 %srl, %lor.ext
+
+  ret i32 %and
+}
Index: llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
===================================================================
--- llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -5150,7 +5150,7 @@
     return V;
 
   if (N0.getOpcode() == ISD::ADD && N1.getOpcode() == ISD::SRL &&
-      VT.getSizeInBits() <= 64) {
+      VT.getSizeInBits() <= 64 && N0->hasOneUse()) {
     if (ConstantSDNode *ADDI = dyn_cast<ConstantSDNode>(N0.getOperand(1))) {
       if (ConstantSDNode *SRLI = dyn_cast<ConstantSDNode>(N1.getOperand(1))) {
         // Look for (and (add x, c1), (lshr y, c2)). If C1 wasn't a legal


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