[llvm] 1e6627e - [X86] matchAddressRecursively - ensure dead nodes are replaced before matching the index register (#82881)

[via llvm-commits]

Author: RicoAfoat
Date: 2024-02-29T14:55:51Z
New Revision: 1e6627ecef42fa8e36dae71589fc17d3adbd18aa

URL: https://github.com/llvm/llvm-project/commit/1e6627ecef42fa8e36dae71589fc17d3adbd18aa
DIFF: https://github.com/llvm/llvm-project/commit/1e6627ecef42fa8e36dae71589fc17d3adbd18aa.diff

LOG: [X86] matchAddressRecursively - ensure dead nodes are replaced before matching the index register (#82881)

Fixes #82431 - see #82431 for more information.

Added: 
    llvm/test/CodeGen/X86/inline-asm-memop.ll

Modified: 
    llvm/lib/Target/X86/X86ISelDAGToDAG.cpp

Removed: 
    


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diff  --git a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
index c8f80ced354538..5cbd9ab4dc2d6c 100644
--- a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
+++ b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
@@ -2732,13 +2732,15 @@ bool X86DAGToDAGISel::matchAddressRecursively(SDValue N, X86ISelAddressMode &AM,
       insertDAGNode(*CurDAG, N, Zext);
       SDValue NewShl = CurDAG->getNode(ISD::SHL, DL, VT, Zext, ShlAmt);
       insertDAGNode(*CurDAG, N, NewShl);
+      CurDAG->ReplaceAllUsesWith(N, NewShl);
+      CurDAG->RemoveDeadNode(N.getNode());
 
       // Convert the shift to scale factor.
       AM.Scale = 1 << ShAmtV;
-      AM.IndexReg = Zext;
-
-      CurDAG->ReplaceAllUsesWith(N, NewShl);
-      CurDAG->RemoveDeadNode(N.getNode());
+      // If matchIndexRecursively is not called here,
+      // Zext may be replaced by other nodes but later used to call a builder
+      // method
+      AM.IndexReg = matchIndexRecursively(Zext, AM, Depth + 1);
       return false;
     }
 

diff  --git a/llvm/test/CodeGen/X86/inline-asm-memop.ll b/llvm/test/CodeGen/X86/inline-asm-memop.ll
new file mode 100644
index 00000000000000..83442498076102
--- /dev/null
+++ b/llvm/test/CodeGen/X86/inline-asm-memop.ll
@@ -0,0 +1,27 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 4
+; RUN: llc -mtriple=x86_64-unknown-linux-gnu -O0 < %s | FileCheck %s
+
+; A bug in X86DAGToDAGISel::matchAddressRecursively create a zext SDValue which
+; is quickly replaced by other SDValue but already pushed into vector for later
+; calling for SelectionDAGISel::Select_INLINEASM getNode builder, see issue
+; 82431 for more infomation.
+
+define void @PR82431(i8 %call, ptr %b) {
+; CHECK-LABEL: PR82431:
+; CHECK:       # %bb.0: # %entry
+; CHECK-NEXT:    movb %dil, %al
+; CHECK-NEXT:    addb $1, %al
+; CHECK-NEXT:    movzbl %al, %eax
+; CHECK-NEXT:    # kill: def $rax killed $eax
+; CHECK-NEXT:    shlq $3, %rax
+; CHECK-NEXT:    addq %rax, %rsi
+; CHECK-NEXT:    #APP
+; CHECK-NEXT:    #NO_APP
+; CHECK-NEXT:    retq
+entry:
+  %narrow = add nuw i8 %call, 1
+  %idxprom = zext i8 %narrow to i64
+  %arrayidx = getelementptr [1 x i64], ptr %b, i64 0, i64 %idxprom
+  tail call void asm "", "=*m,*m,~{dirflag},~{fpsr},~{flags}"(ptr elementtype(i64) %arrayidx, ptr elementtype(i64) %arrayidx)
+  ret void
+}