[llvm] [VPlan] Fold (x | !x) -> true. (PR #177887)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-llvm-transforms

Author: Florian Hahn (fhahn)

<details>
<summary>Changes</summary>



---
Full diff: https://github.com/llvm/llvm-project/pull/177887.diff


3 Files Affected:

- (modified) llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp (+4) 
- (modified) llvm/test/Transforms/LoopVectorize/cse-replicate-regions.ll (+1-3) 
- (modified) llvm/test/Transforms/LoopVectorize/hoist-predicated-loads-with-predicated-stores.ll (+2-4) 


``````````diff
diff --git a/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp b/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
index d1d5870d78a03..a1130f132c827 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
@@ -1280,6 +1280,10 @@ static void simplifyRecipe(VPSingleDefRecipe *Def, VPTypeAnalysis &TypeInfo) {
   if (match(Def, m_c_BinaryOr(m_VPValue(X), m_ZeroInt())))
     return Def->replaceAllUsesWith(X);
 
+  // x | !x -> 1
+  if (match(Def, m_c_BinaryOr(m_VPValue(X), m_Not(m_Deferred(X)))))
+    return Def->replaceAllUsesWith(Plan->getTrue());
+
   // x & 0 -> 0
   if (match(Def, m_c_BinaryAnd(m_VPValue(X), m_ZeroInt())))
     return Def->replaceAllUsesWith(Def->getOperand(Def->getOperand(0) == X));
diff --git a/llvm/test/Transforms/LoopVectorize/cse-replicate-regions.ll b/llvm/test/Transforms/LoopVectorize/cse-replicate-regions.ll
index c0692f3231e89..c0d603c22a5c8 100644
--- a/llvm/test/Transforms/LoopVectorize/cse-replicate-regions.ll
+++ b/llvm/test/Transforms/LoopVectorize/cse-replicate-regions.ll
@@ -95,11 +95,9 @@ define void @multiple_vppredinstphi_with_different_predicate(ptr %A, i32 %d) {
 ; CHECK-NEXT:    br label %[[PRED_SDIV_CONTINUE2]]
 ; CHECK:       [[PRED_SDIV_CONTINUE2]]:
 ; CHECK-NEXT:    [[TMP9:%.*]] = phi <2 x i32> [ [[TMP5]], %[[PRED_SDIV_CONTINUE]] ], [ [[TMP8]], %[[PRED_SDIV_IF1]] ]
-; CHECK-NEXT:    [[TMP10:%.*]] = xor <2 x i1> [[TMP1]], splat (i1 true)
-; CHECK-NEXT:    [[TMP11:%.*]] = or <2 x i1> [[TMP1]], [[TMP10]]
 ; CHECK-NEXT:    [[PREDPHI:%.*]] = select <2 x i1> [[TMP1]], <2 x i32> [[TMP9]], <2 x i32> zeroinitializer
 ; CHECK-NEXT:    [[TMP12:%.*]] = icmp sgt <2 x i32> [[WIDE_LOAD]], splat (i32 20)
-; CHECK-NEXT:    [[TMP13:%.*]] = select <2 x i1> [[TMP11]], <2 x i1> [[TMP12]], <2 x i1> zeroinitializer
+; CHECK-NEXT:    [[TMP13:%.*]] = select <2 x i1> splat (i1 true), <2 x i1> [[TMP12]], <2 x i1> zeroinitializer
 ; CHECK-NEXT:    [[TMP14:%.*]] = extractelement <2 x i1> [[TMP13]], i32 0
 ; CHECK-NEXT:    br i1 [[TMP14]], label %[[PRED_SDIV_IF3:.*]], label %[[PRED_SDIV_CONTINUE4:.*]]
 ; CHECK:       [[PRED_SDIV_IF3]]:
diff --git a/llvm/test/Transforms/LoopVectorize/hoist-predicated-loads-with-predicated-stores.ll b/llvm/test/Transforms/LoopVectorize/hoist-predicated-loads-with-predicated-stores.ll
index 7450fcccbb484..dca1c3fd08382 100644
--- a/llvm/test/Transforms/LoopVectorize/hoist-predicated-loads-with-predicated-stores.ll
+++ b/llvm/test/Transforms/LoopVectorize/hoist-predicated-loads-with-predicated-stores.ll
@@ -1069,10 +1069,8 @@ define void @test_three_stores_with_different_predicates(ptr %dst, ptr %src, ptr
 ; CHECK-NEXT:    store i32 1, ptr [[TMP7]], align 4, !alias.scope [[META95]], !noalias [[META92]]
 ; CHECK-NEXT:    br label %[[PRED_STORE_CONTINUE3]]
 ; CHECK:       [[PRED_STORE_CONTINUE3]]:
-; CHECK-NEXT:    [[TMP8:%.*]] = xor <2 x i1> [[TMP3]], splat (i1 true)
-; CHECK-NEXT:    [[TMP9:%.*]] = or <2 x i1> [[TMP3]], [[TMP8]]
 ; CHECK-NEXT:    [[TMP10:%.*]] = icmp ule <2 x i32> [[WIDE_LOAD]], splat (i32 10)
-; CHECK-NEXT:    [[TMP11:%.*]] = select <2 x i1> [[TMP9]], <2 x i1> [[TMP10]], <2 x i1> zeroinitializer
+; CHECK-NEXT:    [[TMP11:%.*]] = select <2 x i1> splat (i1 true), <2 x i1> [[TMP10]], <2 x i1> zeroinitializer
 ; CHECK-NEXT:    [[TMP12:%.*]] = extractelement <2 x i1> [[TMP11]], i32 0
 ; CHECK-NEXT:    br i1 [[TMP12]], label %[[PRED_STORE_IF4:.*]], label %[[PRED_STORE_CONTINUE5:.*]]
 ; CHECK:       [[PRED_STORE_IF4]]:
@@ -1088,7 +1086,7 @@ define void @test_three_stores_with_different_predicates(ptr %dst, ptr %src, ptr
 ; CHECK-NEXT:    br label %[[PRED_STORE_CONTINUE7]]
 ; CHECK:       [[PRED_STORE_CONTINUE7]]:
 ; CHECK-NEXT:    [[TMP16:%.*]] = icmp ule <2 x i32> [[WIDE_LOAD]], splat (i32 9)
-; CHECK-NEXT:    [[TMP17:%.*]] = select <2 x i1> [[TMP9]], <2 x i1> [[TMP16]], <2 x i1> zeroinitializer
+; CHECK-NEXT:    [[TMP17:%.*]] = select <2 x i1> splat (i1 true), <2 x i1> [[TMP16]], <2 x i1> zeroinitializer
 ; CHECK-NEXT:    [[TMP18:%.*]] = extractelement <2 x i1> [[TMP17]], i32 0
 ; CHECK-NEXT:    br i1 [[TMP18]], label %[[PRED_STORE_IF8:.*]], label %[[PRED_STORE_CONTINUE9:.*]]
 ; CHECK:       [[PRED_STORE_IF8]]:

``````````

</details>


https://github.com/llvm/llvm-project/pull/177887