[llvm] 59f91dd - [InstCombine] Preserve alignment in atomicrmw -> store fold

[Nikita Popov via llvm-commits]

Author: Nikita Popov
Date: 2023-01-09T15:37:24+01:00
New Revision: 59f91ddf90d470e113f9322314ce7c36e21ff0b3

URL: https://github.com/llvm/llvm-project/commit/59f91ddf90d470e113f9322314ce7c36e21ff0b3
DIFF: https://github.com/llvm/llvm-project/commit/59f91ddf90d470e113f9322314ce7c36e21ff0b3.diff

LOG: [InstCombine] Preserve alignment in atomicrmw -> store fold

Preserve the alignment of the original atomicrmw, rather than using
the ABI alignment.

The same problem exists for loads, but that code is being removed
in D141277 anyway.

Added: 
    

Modified: 
    llvm/lib/Transforms/InstCombine/InstCombineAtomicRMW.cpp
    llvm/test/Transforms/InstCombine/atomicrmw.ll

Removed: 
    


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diff  --git a/llvm/lib/Transforms/InstCombine/InstCombineAtomicRMW.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAtomicRMW.cpp
index 0327efbf9614..06d8fb2d474d 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineAtomicRMW.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineAtomicRMW.cpp
@@ -128,10 +128,9 @@ Instruction *InstCombinerImpl::visitAtomicRMWInst(AtomicRMWInst &RMWI) {
     if (Ordering != AtomicOrdering::Release &&
         Ordering != AtomicOrdering::Monotonic)
       return nullptr;
-    auto *SI = new StoreInst(RMWI.getValOperand(),
-                             RMWI.getPointerOperand(), &RMWI);
-    SI->setAtomic(Ordering, RMWI.getSyncScopeID());
-    SI->setAlignment(DL.getABITypeAlign(RMWI.getType()));
+    new StoreInst(RMWI.getValOperand(), RMWI.getPointerOperand(),
+                  /*isVolatile*/ false, RMWI.getAlign(), Ordering,
+                  RMWI.getSyncScopeID(), &RMWI);
     return eraseInstFromFunction(RMWI);
   }
 

diff  --git a/llvm/test/Transforms/InstCombine/atomicrmw.ll b/llvm/test/Transforms/InstCombine/atomicrmw.ll
index b8349196bf0e..7da822b00a63 100644
--- a/llvm/test/Transforms/InstCombine/atomicrmw.ll
+++ b/llvm/test/Transforms/InstCombine/atomicrmw.ll
@@ -289,7 +289,7 @@ define void @xchg_unused_release(ptr %addr) {
 
 define void @xchg_unused_under_aligned(ptr %addr) {
 ; CHECK-LABEL: @xchg_unused_under_aligned(
-; CHECK-NEXT:    store atomic i32 -1, ptr [[ADDR:%.*]] release, align 4
+; CHECK-NEXT:    store atomic i32 -1, ptr [[ADDR:%.*]] release, align 1
 ; CHECK-NEXT:    ret void
 ;
   atomicrmw xchg ptr %addr, i32 -1 release, align 1
@@ -298,7 +298,7 @@ define void @xchg_unused_under_aligned(ptr %addr) {
 
 define void @xchg_unused_over_aligned(ptr %addr) {
 ; CHECK-LABEL: @xchg_unused_over_aligned(
-; CHECK-NEXT:    store atomic i32 -1, ptr [[ADDR:%.*]] release, align 4
+; CHECK-NEXT:    store atomic i32 -1, ptr [[ADDR:%.*]] release, align 8
 ; CHECK-NEXT:    ret void
 ;
   atomicrmw xchg ptr %addr, i32 -1 release, align 8