[llvm] 72ba248 - [PatternMatch] don't match a scalar select of bool vectors as a logical-and or logical-or

[Sanjay Patel via llvm-commits]

Author: Sanjay Patel
Date: 2022-11-01T14:50:18-04:00
New Revision: 72ba2489f2c7b0a911bd23e50aaaca6eae9a183e

URL: https://github.com/llvm/llvm-project/commit/72ba2489f2c7b0a911bd23e50aaaca6eae9a183e
DIFF: https://github.com/llvm/llvm-project/commit/72ba2489f2c7b0a911bd23e50aaaca6eae9a183e.diff

LOG: [PatternMatch] don't match a scalar select of bool vectors as a logical-and or logical-or

Most folds based on these matchers already check to make sure the
condition type is the same as the select type, and it seems unlikely
that a fold would want to handle a scalar-select-of-vectors pattern
(there are no regression tests for it).

This is a preliminary step for fixing #issue 58552. The fold(s)
responsible for that crash (D101807, D101375) don't use the matchers
yet, but they probably should.

Differential Revision: https://reviews.llvm.org/D137170

Added: 
    

Modified: 
    llvm/include/llvm/IR/PatternMatch.h
    llvm/unittests/IR/PatternMatch.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/include/llvm/IR/PatternMatch.h b/llvm/include/llvm/IR/PatternMatch.h
index 31ff63c8b6603..2901c6456c998 100644
--- a/llvm/include/llvm/IR/PatternMatch.h
+++ b/llvm/include/llvm/IR/PatternMatch.h
@@ -2513,6 +2513,12 @@ struct LogicalOp_match {
       auto *Cond = Select->getCondition();
       auto *TVal = Select->getTrueValue();
       auto *FVal = Select->getFalseValue();
+
+      // Don't match a scalar select of bool vectors.
+      // Transforms expect a single type for operands if this matches.
+      if (Cond->getType() != Select->getType())
+        return false;
+
       if (Opcode == Instruction::And) {
         auto *C = dyn_cast<Constant>(FVal);
         if (C && C->isNullValue())

diff  --git a/llvm/unittests/IR/PatternMatch.cpp b/llvm/unittests/IR/PatternMatch.cpp
index d2ec259ec8287..ab35df016cdda 100644
--- a/llvm/unittests/IR/PatternMatch.cpp
+++ b/llvm/unittests/IR/PatternMatch.cpp
@@ -1730,10 +1730,12 @@ TEST_F(PatternMatchTest, VectorLogicalSelects) {
   // select i1 Scalar, <3 x i1> <i1 1, i1 1, i1 1>, <3 x i1> Vector
   Value *MixedTypeOr = IRB.CreateSelect(Scalar, T, Vector);
 
+  // We allow matching a real vector logical select,
+  // but not a scalar select of vector bools.
   EXPECT_TRUE(match(VecAnd, m_LogicalAnd(m_Value(), m_Value())));
-  EXPECT_TRUE(match(MixedTypeAnd, m_LogicalAnd(m_Value(), m_Value())));
+  EXPECT_FALSE(match(MixedTypeAnd, m_LogicalAnd(m_Value(), m_Value())));
   EXPECT_TRUE(match(VecOr, m_LogicalOr(m_Value(), m_Value())));
-  EXPECT_TRUE(match(MixedTypeOr, m_LogicalOr(m_Value(), m_Value())));
+  EXPECT_FALSE(match(MixedTypeOr, m_LogicalOr(m_Value(), m_Value())));
 }
 
 TEST_F(PatternMatchTest, VScale) {