[llvm] [X86] combineAndNotOrIntoAndNotAnd - don't fold other constant operands (PR #113264)

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Mon Oct 21 21:59:31 PDT 2024


llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-backend-x86

Author: Miguel Saldivar (Saldivarcher)

<details>
<summary>Changes</summary>



---
Full diff: https://github.com/llvm/llvm-project/pull/113264.diff


2 Files Affected:

- (modified) llvm/lib/Target/X86/X86ISelLowering.cpp (+2-2) 
- (modified) llvm/test/CodeGen/X86/pr108731.ll (+20) 


``````````diff
diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index bcb84add65d83e..5ae5a7dbe0f6da 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -50049,8 +50049,8 @@ static SDValue combineAndNotOrIntoAndNotAnd(SDNode *N, SelectionDAG &DAG) {
   SDValue X, Y, Z;
   if (sd_match(N, m_And(m_Value(X),
                         m_OneUse(m_Or(m_Value(Y), m_Not(m_Value(Z))))))) {
-    // Don't fold if Y is a constant to prevent infinite loops.
-    if (!isa<ConstantSDNode>(Y))
+    // Don't fold if Y and Z are constants to prevent infinite loops.
+    if (!isa<ConstantSDNode>(Y) && !isa<ConstantSDNode>(Z))
       return DAG.getNode(
           ISD::AND, DL, VT, X,
           DAG.getNOT(
diff --git a/llvm/test/CodeGen/X86/pr108731.ll b/llvm/test/CodeGen/X86/pr108731.ll
index 473b4f7f4da2e3..2983d108eaeddc 100644
--- a/llvm/test/CodeGen/X86/pr108731.ll
+++ b/llvm/test/CodeGen/X86/pr108731.ll
@@ -192,3 +192,23 @@ define void @PR112347(ptr %p0, ptr %p1, ptr %p2) {
   ret void
 }
 
+define void @PR113240(i64 %a) {
+; CHECK-LABEL: PR113240:
+; CHECK:       # %bb.0: # %entry
+; CHECK-NEXT:    movq %rdi, %rax
+; CHECK-NEXT:    notq %rax
+; CHECK-NEXT:    movabsq $8796093022206, %rcx # imm = 0x7FFFFFFFFFE
+; CHECK-NEXT:    notq %rcx
+; CHECK-NEXT:    orq %rax, %rcx
+; CHECK-NEXT:    andq %rdi, %rcx
+; CHECK-NEXT:    movq %rcx, 0
+; CHECK-NEXT:    retq
+entry:
+  %and = and i64 %a, 8796093022206
+  %bf.value = and i64 8796093022206, 0
+  %not = xor i64 %and, -1
+  %and4 = and i64 %a, %not
+  store i64 %and4, ptr null, align 8
+  ret void
+}
+

``````````

</details>


https://github.com/llvm/llvm-project/pull/113264


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