[llvm] [SLP]Better sorting of phi instructions by comparing type sizes (PR #102188)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-llvm-transforms

Author: Alexey Bataev (alexey-bataev)

<details>
<summary>Changes</summary>

Currently SLP vectorizer compares phi instructions by the type id of the
compared instructions, which may failed in case of different integer types,
with the different sizes. Patch adds comparison by type sizes to fix this.


---
Full diff: https://github.com/llvm/llvm-project/pull/102188.diff


2 Files Affected:

- (modified) llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp (+6) 
- (modified) llvm/test/Transforms/SLPVectorizer/X86/landing_pad.ll (+5-6) 


``````````diff
diff --git a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
index 9589d306581e6..17cc202254b3a 100644
--- a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
+++ b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
@@ -18719,6 +18719,12 @@ bool SLPVectorizerPass::vectorizeChainsInBlock(BasicBlock *BB, BoUpSLP &R) {
       return true;
     if (V1->getType()->getTypeID() > V2->getType()->getTypeID())
       return false;
+    if (V1->getType()->getScalarSizeInBits() <
+        V2->getType()->getScalarSizeInBits())
+      return true;
+    if (V1->getType()->getScalarSizeInBits() >
+        V2->getType()->getScalarSizeInBits())
+      return false;
     ArrayRef<Value *> Opcodes1 = PHIToOpcodes[V1];
     ArrayRef<Value *> Opcodes2 = PHIToOpcodes[V2];
     if (Opcodes1.size() < Opcodes2.size())
diff --git a/llvm/test/Transforms/SLPVectorizer/X86/landing_pad.ll b/llvm/test/Transforms/SLPVectorizer/X86/landing_pad.ll
index 21e66548d9100..47b42bc8f32a7 100644
--- a/llvm/test/Transforms/SLPVectorizer/X86/landing_pad.ll
+++ b/llvm/test/Transforms/SLPVectorizer/X86/landing_pad.ll
@@ -10,7 +10,7 @@ define void @foo() personality ptr @bar {
 ; CHECK:       bb2.loopexit:
 ; CHECK-NEXT:    br label [[BB2:%.*]]
 ; CHECK:       bb2:
-; CHECK-NEXT:    [[TMP0:%.*]] = phi <4 x i32> [ [[TMP8:%.*]], [[BB9:%.*]] ], [ poison, [[BB2_LOOPEXIT:%.*]] ]
+; CHECK-NEXT:    [[TMP0:%.*]] = phi <4 x i32> [ [[TMP7:%.*]], [[BB9:%.*]] ], [ poison, [[BB2_LOOPEXIT:%.*]] ]
 ; CHECK-NEXT:    ret void
 ; CHECK:       bb3:
 ; CHECK-NEXT:    [[TMP1:%.*]] = phi <2 x i32> [ [[TMP3:%.*]], [[BB6:%.*]] ], [ poison, [[BB1:%.*]] ]
@@ -32,19 +32,18 @@ define void @foo() personality ptr @bar {
 ; CHECK-NEXT:    br i1 poison, label [[BB7]], label [[BB6]]
 ; CHECK:       bb9:
 ; CHECK-NEXT:    [[INDVARS_IV528799:%.*]] = phi i64 [ poison, [[BB10]] ], [ poison, [[BB12]] ]
-; CHECK-NEXT:    [[TMP6:%.*]] = phi <2 x i32> [ [[TMP9:%.*]], [[BB10]] ], [ [[TMP10:%.*]], [[BB12]] ]
-; CHECK-NEXT:    [[TMP7:%.*]] = shufflevector <2 x i32> [[TMP6]], <2 x i32> poison, <4 x i32> <i32 1, i32 0, i32 poison, i32 poison>
-; CHECK-NEXT:    [[TMP8]] = shufflevector <4 x i32> [[TMP7]], <4 x i32> poison, <4 x i32> <i32 poison, i32 poison, i32 0, i32 1>
+; CHECK-NEXT:    [[TMP6:%.*]] = phi <2 x i32> [ [[TMP8:%.*]], [[BB10]] ], [ [[TMP9:%.*]], [[BB12]] ]
+; CHECK-NEXT:    [[TMP7]] = shufflevector <2 x i32> [[TMP6]], <2 x i32> poison, <4 x i32> <i32 poison, i32 poison, i32 1, i32 0>
 ; CHECK-NEXT:    br label [[BB2]]
 ; CHECK:       bb10:
-; CHECK-NEXT:    [[TMP9]] = phi <2 x i32> [ [[TMP1]], [[BB3]] ]
+; CHECK-NEXT:    [[TMP8]] = phi <2 x i32> [ [[TMP1]], [[BB3]] ]
 ; CHECK-NEXT:    [[LANDING_PAD68:%.*]] = landingpad { ptr, i32 }
 ; CHECK-NEXT:            cleanup
 ; CHECK-NEXT:    br label [[BB9]]
 ; CHECK:       bb11:
 ; CHECK-NEXT:    ret void
 ; CHECK:       bb12:
-; CHECK-NEXT:    [[TMP10]] = phi <2 x i32> [ [[TMP4]], [[BB7]] ]
+; CHECK-NEXT:    [[TMP9]] = phi <2 x i32> [ [[TMP4]], [[BB7]] ]
 ; CHECK-NEXT:    [[LANDING_PAD149:%.*]] = landingpad { ptr, i32 }
 ; CHECK-NEXT:            cleanup
 ; CHECK-NEXT:    br label [[BB9]]

``````````

</details>


https://github.com/llvm/llvm-project/pull/102188