[llvm] 34362c6 - LoopIdiomRecognize: update comment about ctpop (NFC) (#70812)

[via llvm-commits]

Author: Ramkumar Ramachandra
Date: 2023-10-31T14:55:23Z
New Revision: 34362c6ec6635a22910d5dce339b0934c799ebf6

URL: https://github.com/llvm/llvm-project/commit/34362c6ec6635a22910d5dce339b0934c799ebf6
DIFF: https://github.com/llvm/llvm-project/commit/34362c6ec6635a22910d5dce339b0934c799ebf6.diff

LOG: LoopIdiomRecognize: update comment about ctpop (NFC) (#70812)

Ever since 95de7c3, LoopIdiomRecognize has been able to recognize the
ctpop idiom, with target-specific lowering information. However, the
comment in the header about ctpop not being recognized is outdated.
Remove it.

Added: 
    

Modified: 
    llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp

Removed: 
    


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diff  --git a/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp b/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
index b85178585e0ada0..3b2a7b03dd6d34e 100644
--- a/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
@@ -24,12 +24,6 @@
 //   memcmp, strlen, etc.
 // Future floating point idioms to recognize in -ffast-math mode:
 //   fpowi
-// Future integer operation idioms to recognize:
-//   ctpop
-//
-// Beware that isel's default lowering for ctpop is highly inefficient for
-// i64 and larger types when i64 is legal and the value has few bits set.  It
-// would be good to enhance isel to emit a loop for ctpop in this case.
 //
 // This could recognize common matrix multiplies and dot product idioms and
 // replace them with calls to BLAS (if linked in??).