[llvm] 7fde990 - Recommit "[Local] Simplify the alignment limits in getOrEnforceKnownAlignment. NFCI"

[Craig Topper via llvm-commits]

Author: Craig Topper
Date: 2020-04-18T13:51:57-07:00
New Revision: 7fde990694f5d1fc4812c4e77e86899e61783b8a

URL: https://github.com/llvm/llvm-project/commit/7fde990694f5d1fc4812c4e77e86899e61783b8a
DIFF: https://github.com/llvm/llvm-project/commit/7fde990694f5d1fc4812c4e77e86899e61783b8a.diff

LOG: Recommit "[Local] Simplify the alignment limits in getOrEnforceKnownAlignment. NFCI"

With a tweak to avoid a linker error for passing
MaxAlignmentExponent by reference to std::min.

Added: 
    

Modified: 
    llvm/lib/Transforms/Utils/Local.cpp

Removed: 
    


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diff  --git a/llvm/lib/Transforms/Utils/Local.cpp b/llvm/lib/Transforms/Utils/Local.cpp
index b9dff8c02ce4..d941d5f0ffc6 100644
--- a/llvm/lib/Transforms/Utils/Local.cpp
+++ b/llvm/lib/Transforms/Utils/Local.cpp
@@ -1215,13 +1215,11 @@ unsigned llvm::getOrEnforceKnownAlignment(Value *V, unsigned PrefAlign,
 
   // Avoid trouble with ridiculously large TrailZ values, such as
   // those computed from a null pointer.
-  TrailZ = std::min(TrailZ, unsigned(sizeof(unsigned) * CHAR_BIT - 1));
+  // LLVM doesn't support alignments larger than (1 << MaxAlignmentExponent).
+  TrailZ = std::min(TrailZ, +Value::MaxAlignmentExponent);
 
   unsigned Align = 1u << std::min(Known.getBitWidth() - 1, TrailZ);
 
-  // LLVM doesn't support alignments larger than this currently.
-  Align = std::min(Align, +Value::MaximumAlignment);
-
   if (PrefAlign > Align)
     Align = enforceKnownAlignment(V, Align, PrefAlign, DL);