[llvm] 7103c87 - Reland "[InstCombine] Lower infinite combine loop detection thresholds""

[Roman Lebedev via llvm-commits]

Author: Roman Lebedev
Date: 2020-07-10T17:49:16+03:00
New Revision: 7103c87596efccd532e9fe04a6ba6a200fed8481

URL: https://github.com/llvm/llvm-project/commit/7103c87596efccd532e9fe04a6ba6a200fed8481
DIFF: https://github.com/llvm/llvm-project/commit/7103c87596efccd532e9fe04a6ba6a200fed8481.diff

LOG: Reland "[InstCombine] Lower infinite combine loop detection thresholds""

This relands commit cd7f8051ac7b6f08734102446482c1e5d951bfcc that was
reverted since lower threshold have successfully found an issue.
Now that the issue is fixed, let's wait until the next one is reported.

This reverts commit caa423eef0d128f35ac11ddbce34964caafb61c1.

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"),