[Mlir-commits] [mlir] cb395b8 - [MLIR] Add not icmp canonicalization documentation

[William S. Moses]

Author: William S. Moses
Date: 2021-05-04T11:44:25-04:00
New Revision: cb395b84b09d1d411f65ae97f25c3a7a05b9bb7f

URL: https://github.com/llvm/llvm-project/commit/cb395b84b09d1d411f65ae97f25c3a7a05b9bb7f
DIFF: https://github.com/llvm/llvm-project/commit/cb395b84b09d1d411f65ae97f25c3a7a05b9bb7f.diff

LOG: [MLIR] Add not icmp canonicalization documentation

See: https://reviews.llvm.org/D101710

Added: 
    

Modified: 
    mlir/lib/Dialect/StandardOps/IR/Ops.cpp

Removed: 
    


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diff  --git a/mlir/lib/Dialect/StandardOps/IR/Ops.cpp b/mlir/lib/Dialect/StandardOps/IR/Ops.cpp
index 5b10e12c248eb..04464af904c09 100644
--- a/mlir/lib/Dialect/StandardOps/IR/Ops.cpp
+++ b/mlir/lib/Dialect/StandardOps/IR/Ops.cpp
@@ -3013,12 +3013,14 @@ OpFoldResult XOrOp::fold(ArrayRef<Attribute> operands) {
 
 namespace {
 /// Replace a not of a comparison operation, for example: not(cmp eq A, B) =>
-/// cmp ne A, B. Note that a logical not is implemented as xor 1, val
+/// cmp ne A, B. Note that a logical not is implemented as xor 1, val.
 struct NotICmp : public OpRewritePattern<XOrOp> {
   using OpRewritePattern<XOrOp>::OpRewritePattern;
 
   LogicalResult matchAndRewrite(XOrOp op,
                                 PatternRewriter &rewriter) const override {
+    // Commutative ops (such as xor) have the constant appear second, which
+    // we assume here.
 
     APInt constValue;
     if (!matchPattern(op.getOperand(1), m_ConstantInt(&constValue)))