[PATCH] D158527: [InstCombine] Add a cl::opt to control calls to getOrEnforceKnownAlignment in LoadInst and StoreInst

[Dhruv Chawla via Phabricator via llvm-commits]

0xdc03 updated this revision to Diff 556958.
0xdc03 added a comment.

- Rebase on main


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D158527/new/

https://reviews.llvm.org/D158527

Files:
  llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp


Index: llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
===================================================================
--- llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
+++ llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
@@ -36,6 +36,8 @@
     cl::desc("Maximum users to visit in copy from constant transform"),
     cl::Hidden);
 
+extern cl::opt<bool> EnableInferAlignmentPass;
+
 /// isOnlyCopiedFromConstantMemory - Recursively walk the uses of a (derived)
 /// pointer to an alloca.  Ignore any reads of the pointer, return false if we
 /// see any stores or other unknown uses.  If we see pointer arithmetic, keep
@@ -1048,11 +1050,13 @@
   if (Instruction *Res = combineLoadToOperationType(*this, LI))
     return Res;
 
-  // Attempt to improve the alignment.
-  Align KnownAlign = getOrEnforceKnownAlignment(
-      Op, DL.getPrefTypeAlign(LI.getType()), DL, &LI, &AC, &DT);
-  if (KnownAlign > LI.getAlign())
-    LI.setAlignment(KnownAlign);
+  if (!EnableInferAlignmentPass) {
+    // Attempt to improve the alignment.
+    Align KnownAlign = getOrEnforceKnownAlignment(
+        Op, DL.getPrefTypeAlign(LI.getType()), DL, &LI, &AC, &DT);
+    if (KnownAlign > LI.getAlign())
+      LI.setAlignment(KnownAlign);
+  }
 
   // Replace GEP indices if possible.
   if (Instruction *NewGEPI = replaceGEPIdxWithZero(*this, Op, LI))
@@ -1445,11 +1449,13 @@
   if (combineStoreToValueType(*this, SI))
     return eraseInstFromFunction(SI);
 
-  // Attempt to improve the alignment.
-  const Align KnownAlign = getOrEnforceKnownAlignment(
-      Ptr, DL.getPrefTypeAlign(Val->getType()), DL, &SI, &AC, &DT);
-  if (KnownAlign > SI.getAlign())
-    SI.setAlignment(KnownAlign);
+  if (!EnableInferAlignmentPass) {
+    // Attempt to improve the alignment.
+    const Align KnownAlign = getOrEnforceKnownAlignment(
+        Ptr, DL.getPrefTypeAlign(Val->getType()), DL, &SI, &AC, &DT);
+    if (KnownAlign > SI.getAlign())
+      SI.setAlignment(KnownAlign);
+  }
 
   // Try to canonicalize the stored type.
   if (unpackStoreToAggregate(*this, SI))


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D158527.556958.patch
Type: text/x-patch
Size: 2103 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20230918/56213b4b/attachment.bin>