[llvm] Fix Failure to fold (and %x, (sext i1 %m)) -> (select %m, %x, 0) with multiple uses of %m Resolve #81288 (PR #81409)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-llvm-transforms

Author: None (SahilPatidar)

<details>
<summary>Changes</summary>

Resolve #<!-- -->81288

---
Full diff: https://github.com/llvm/llvm-project/pull/81409.diff


2 Files Affected:

- (modified) llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp (+1-1) 
- (modified) llvm/test/Transforms/InstCombine/and.ll (+17-2) 


``````````diff
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
index 5fd944a859ef09..516af05b4cc531 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
@@ -2637,7 +2637,7 @@ Instruction *InstCombinerImpl::visitAnd(BinaryOperator &I) {
   //       arm may not be reversible due to poison semantics. Is that a good
   //       canonicalization?
   Value *A, *B;
-  if (match(&I, m_c_And(m_OneUse(m_SExt(m_Value(A))), m_Value(B))) &&
+  if (match(&I, m_c_And(m_SExt(m_Value(A)), m_Value(B))) &&
       A->getType()->isIntOrIntVectorTy(1))
     return SelectInst::Create(A, B, Constant::getNullValue(Ty));
 
diff --git a/llvm/test/Transforms/InstCombine/and.ll b/llvm/test/Transforms/InstCombine/and.ll
index 2e37fee07cc47b..0931c7a1c4053d 100644
--- a/llvm/test/Transforms/InstCombine/and.ll
+++ b/llvm/test/Transforms/InstCombine/and.ll
@@ -1818,7 +1818,7 @@ define i8 @not_ashr_bitwidth_mask_use2(i8 %x, i8 %y) {
 ; CHECK-NEXT:    [[ISNOTNEG:%.*]] = icmp sgt i8 [[X:%.*]], -1
 ; CHECK-NEXT:    [[NOT:%.*]] = sext i1 [[ISNOTNEG]] to i8
 ; CHECK-NEXT:    call void @use8(i8 [[NOT]])
-; CHECK-NEXT:    [[R:%.*]] = and i8 [[NOT]], [[Y:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = select i1 [[ISNOTNEG]], i8 [[Y:%.*]], i8 0
 ; CHECK-NEXT:    ret i8 [[R]]
 ;
   %sign = ashr i8 %x, 7
@@ -1925,7 +1925,7 @@ define i16 @invert_signbit_splat_mask_use3(i8 %x, i16 %y) {
 ; CHECK-NEXT:    [[ISNOTNEG:%.*]] = icmp sgt i8 [[X:%.*]], -1
 ; CHECK-NEXT:    [[S:%.*]] = sext i1 [[ISNOTNEG]] to i16
 ; CHECK-NEXT:    call void @use16(i16 [[S]])
-; CHECK-NEXT:    [[R:%.*]] = and i16 [[S]], [[Y:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = select i1 [[ISNOTNEG]], i16 [[Y:%.*]], i16 0
 ; CHECK-NEXT:    ret i16 [[R]]
 ;
   %a = ashr i8 %x, 7
@@ -2768,3 +2768,18 @@ define i32 @add_constant_equal_with_the_top_bit_of_demandedbits_insertpt(i32 %x,
   %and = and i32 %or, 24
   ret i32 %and
 }
+
+define i32 @and_sext(i32 %x, i32 %y, i32 %a, i32 %b) {
+; CHECK-LABEL: @and_sext(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i32 [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    [[TMP1:%.*]] = add i32 [[A:%.*]], [[B:%.*]]
+; CHECK-NEXT:    [[ADD:%.*]] = select i1 [[CMP]], i32 [[TMP1]], i32 0
+; CHECK-NEXT:    ret i32 [[ADD]]
+;
+  %cmp = icmp sgt i32 %x, %y
+  %sext = sext i1 %cmp to i32
+  %and1 = and i32 %sext, %a
+  %and2 = and i32 %sext, %b
+  %add = add i32 %and1, %and2
+  ret i32 %add
+}

``````````

</details>


https://github.com/llvm/llvm-project/pull/81409