[PATCH] D116728: [LICM] Check for noalias call instead of alloc like fn

[Nikita Popov via Phabricator via llvm-commits]

This revision was landed with ongoing or failed builds.
This revision was automatically updated to reflect the committed changes.
Closed by commit rG41a522779dff: [LICM] Check for noalias call instead of alloc like fn (authored by nikic).

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D116728/new/

https://reviews.llvm.org/D116728

Files:
  llvm/lib/Transforms/Scalar/LICM.cpp
  llvm/test/Transforms/LICM/promote-tls.ll


Index: llvm/test/Transforms/LICM/promote-tls.ll
===================================================================
--- llvm/test/Transforms/LICM/promote-tls.ll
+++ llvm/test/Transforms/LICM/promote-tls.ll
@@ -156,15 +156,18 @@
 ; CHECK-NEXT:    [[EXITCMP:%.*]] = icmp eq i8* [[GUARD]], null
 ; CHECK-NEXT:    br i1 [[EXITCMP]], label [[FOR_BODY]], label [[EARLY_EXIT:%.*]]
 ; CHECK:       early-exit:
+; CHECK-NEXT:    [[NEW1_LCSSA:%.*]] = phi i32 [ [[NEW1]], [[FOR_HEADER]] ]
+; CHECK-NEXT:    store i32 [[NEW1_LCSSA]], i32* [[ADDR]], align 4
 ; CHECK-NEXT:    ret i32* null
 ; CHECK:       for.body:
 ; CHECK-NEXT:    [[NEW]] = add i32 [[NEW1]], 1
-; CHECK-NEXT:    store i32 [[NEW]], i32* [[ADDR]], align 4
 ; CHECK-NEXT:    [[INC]] = add nsw i32 [[I_02]], 1
 ; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i32 [[INC]], [[N:%.*]]
 ; CHECK-NEXT:    br i1 [[CMP]], label [[FOR_HEADER]], label [[FOR_COND_FOR_END_CRIT_EDGE:%.*]]
 ; CHECK:       for.cond.for.end_crit_edge:
+; CHECK-NEXT:    [[NEW_LCSSA:%.*]] = phi i32 [ [[NEW]], [[FOR_BODY]] ]
 ; CHECK-NEXT:    [[SPLIT:%.*]] = phi i32* [ [[ADDR]], [[FOR_BODY]] ]
+; CHECK-NEXT:    store i32 [[NEW_LCSSA]], i32* [[ADDR]], align 4
 ; CHECK-NEXT:    ret i32* null
 ;
 entry:
Index: llvm/lib/Transforms/Scalar/LICM.cpp
===================================================================
--- llvm/lib/Transforms/Scalar/LICM.cpp
+++ llvm/lib/Transforms/Scalar/LICM.cpp
@@ -1925,8 +1925,7 @@
 
 /// Return true iff we can prove that a caller of this function can not inspect
 /// the contents of the provided object in a well defined program.
-bool isKnownNonEscaping(Value *Object, const Loop *L,
-                        const TargetLibraryInfo *TLI, DominatorTree *DT) {
+bool isKnownNonEscaping(Value *Object, const Loop *L, DominatorTree *DT) {
   if (isa<AllocaInst>(Object))
     // Since the alloca goes out of scope, we know the caller can't retain a
     // reference to it and be well defined.  Thus, we don't need to check for
@@ -1939,11 +1938,8 @@
   //   1) Object can't be escaped by this function.  This is what
   //      PointerMayBeCaptured checks.
   //   2) Object can't have been captured at definition site.  For this, we
-  //      need to know the return value is noalias.  At the moment, we use a
-  //      weaker condition and handle only AllocLikeFunctions (which are
-  //      known to be noalias).  TODO
-  return isAllocLikeFn(Object, TLI) &&
-         isNotCapturedBeforeOrInLoop(Object, L, DT);
+  //      need to know the return value is noalias.
+  return isNoAliasCall(Object) && isNotCapturedBeforeOrInLoop(Object, L, DT);
 }
 
 } // namespace
@@ -2030,7 +2026,7 @@
     // this by proving that the caller can't have a reference to the object
     // after return and thus can't possibly load from the object.
     Value *Object = getUnderlyingObject(SomePtr);
-    if (!isKnownNonEscaping(Object, CurLoop, TLI, DT))
+    if (!isKnownNonEscaping(Object, CurLoop, DT))
       return false;
     // Subtlety: Alloca's aren't visible to callers, but *are* potentially
     // visible to other threads if captured and used during their lifetimes.
@@ -2163,7 +2159,7 @@
     else {
       Value *Object = getUnderlyingObject(SomePtr);
       SafeToInsertStore =
-          (isAllocLikeFn(Object, TLI) || isa<AllocaInst>(Object)) &&
+          (isNoAliasCall(Object) || isa<AllocaInst>(Object)) &&
           isNotCapturedBeforeOrInLoop(Object, CurLoop, DT);
     }
   }


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D116728.397861.patch
Type: text/x-patch
Size: 3444 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20220106/7c59082d/attachment.bin>