[llvm] cd7f805 - [InstCombine] Lower infinite combine loop detection thresholds

[Roman Lebedev via llvm-commits]

Author: Roman Lebedev
Date: 2020-07-06T13:19:31+03:00
New Revision: cd7f8051ac7b6f08734102446482c1e5d951bfcc

URL: https://github.com/llvm/llvm-project/commit/cd7f8051ac7b6f08734102446482c1e5d951bfcc
DIFF: https://github.com/llvm/llvm-project/commit/cd7f8051ac7b6f08734102446482c1e5d951bfcc.diff

LOG: [InstCombine] Lower infinite combine loop detection thresholds

Summary:
1000 iteratons is still kinda a lot.
Would it make sense to iteratively lower it, until it becomes `2`,
with some delay inbetween in order to let users actually potentially encounter it?

Reviewers: spatel, nikic, kuhar

Reviewed By: nikic

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D83160

Added: 
    

Modified: 
    llvm/lib/Transforms/InstCombine/InstructionCombining.cpp

Removed: 
    


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diff  --git a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
index d1c1e5418825..e810b3de25bc 100644
--- a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -123,8 +123,13 @@ STATISTIC(NumReassoc  , "Number of reassociations");
 DEBUG_COUNTER(VisitCounter, "instcombine-visit",
               "Controls which instructions are visited");
 
+// FIXME: these limits eventually should be as low as 2.
 static constexpr unsigned InstCombineDefaultMaxIterations = 1000;
+#ifndef NDEBUG
+static constexpr unsigned InstCombineDefaultInfiniteLoopThreshold = 100;
+#else
 static constexpr unsigned InstCombineDefaultInfiniteLoopThreshold = 1000;
+#endif
 
 static cl::opt<bool>
 EnableCodeSinking("instcombine-code-sinking", cl::desc("Enable code sinking"),