[llvm] 541c284 - Revert "[CaptureTracking] Do not check domination"

[Nikita Popov via llvm-commits]

Author: Nikita Popov
Date: 2021-05-16T11:04:45+02:00
New Revision: 541c2845ded174f8937433fc8a110a2e644919a6

URL: https://github.com/llvm/llvm-project/commit/541c2845ded174f8937433fc8a110a2e644919a6
DIFF: https://github.com/llvm/llvm-project/commit/541c2845ded174f8937433fc8a110a2e644919a6.diff

LOG: Revert "[CaptureTracking] Do not check domination"

This reverts commit 6b8b43e7af3074124e3c9e429e1fb08165799be4.

This causes clang test to fail (CodeGenObjC/synchronized.m).
Revert until I can figure out whether that's an expected change.

Added: 
    

Modified: 
    llvm/lib/Analysis/CaptureTracking.cpp
    llvm/test/Transforms/MemCpyOpt/callslot.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Analysis/CaptureTracking.cpp b/llvm/lib/Analysis/CaptureTracking.cpp
index 25815fc57463..e14f6f25dc18 100644
--- a/llvm/lib/Analysis/CaptureTracking.cpp
+++ b/llvm/lib/Analysis/CaptureTracking.cpp
@@ -143,8 +143,14 @@ namespace {
         return !isPotentiallyReachableFromMany(Worklist, BB, nullptr, DT);
       }
 
+      // If the value is defined in the same basic block as use and BeforeHere,
+      // there is no need to explore the use if BeforeHere dominates use.
       // Check whether there is a path from I to BeforeHere.
-      return !isPotentiallyReachable(I, BeforeHere, nullptr, DT);
+      if (DT->dominates(BeforeHere, I) &&
+          !isPotentiallyReachable(I, BeforeHere, nullptr, DT))
+        return true;
+
+      return false;
     }
 
     bool captured(const Use *U) override {

diff  --git a/llvm/test/Transforms/MemCpyOpt/callslot.ll b/llvm/test/Transforms/MemCpyOpt/callslot.ll
index b9eab2ef8778..037a95ec5176 100644
--- a/llvm/test/Transforms/MemCpyOpt/callslot.ll
+++ b/llvm/test/Transforms/MemCpyOpt/callslot.ll
@@ -252,8 +252,8 @@ define void @capture_nopath_call(i1 %cond) {
 ; CHECK-NEXT:    call void @accept_ptr(i8* [[DEST_I8]])
 ; CHECK-NEXT:    ret void
 ; CHECK:       nocaptures:
-; CHECK-NEXT:    [[DEST1:%.*]] = bitcast [16 x i8]* [[DEST]] to i8*
-; CHECK-NEXT:    call void @accept_ptr(i8* [[DEST1]]) #[[ATTR3]]
+; CHECK-NEXT:    call void @accept_ptr(i8* [[SRC_I8]]) #[[ATTR3]]
+; CHECK-NEXT:    call void @llvm.memcpy.p0i8.p0i8.i64(i8* [[DEST_I8]], i8* [[SRC_I8]], i64 16, i1 false)
 ; CHECK-NEXT:    ret void
 ;
   %dest = alloca [16 x i8]