[llvm] 02c9e89 - [InstCombine][MemProf] Preserve all metadata (#169242)

via llvm-commits llvm-commits at lists.llvm.org
Tue Nov 25 07:56:11 PST 2025


Author: Marco Elver
Date: 2025-11-25T16:56:06+01:00
New Revision: 02c9e8987a22753417c721eba5e5848f3fe33a24

URL: https://github.com/llvm/llvm-project/commit/02c9e8987a22753417c721eba5e5848f3fe33a24
DIFF: https://github.com/llvm/llvm-project/commit/02c9e8987a22753417c721eba5e5848f3fe33a24.diff

LOG: [InstCombine][MemProf] Preserve all metadata (#169242)

When rewriting operator new calls to their hot/cold variants for PGHO,
`!alloc_token` metadata was being dropped. This metadata is required by
the AllocToken pass to correctly instrument the optimized allocation.

Fix it by preserving all metadata.

Added: 
    

Modified: 
    llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
    llvm/test/Transforms/InstCombine/simplify-libcalls-new.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp b/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
index 4f4e64b1c7b70..d1548694baa27 100644
--- a/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
@@ -1806,119 +1806,124 @@ Value *LibCallSimplifier::optimizeNew(CallInst *CI, IRBuilderBase &B,
   // better to replace the hinted call with a non hinted call, to avoid the
   // extra parameter and the if condition check of the hint value in the
   // allocator. This can be considered in the future.
+  Value *NewCall = nullptr;
   switch (Func) {
   case LibFunc_Znwm12__hot_cold_t:
     if (OptimizeExistingHotColdNew)
-      return emitHotColdNew(CI->getArgOperand(0), B, TLI,
-                            LibFunc_Znwm12__hot_cold_t, HotCold);
+      NewCall = emitHotColdNew(CI->getArgOperand(0), B, TLI,
+                               LibFunc_Znwm12__hot_cold_t, HotCold);
     break;
   case LibFunc_Znwm:
-    return emitHotColdNew(CI->getArgOperand(0), B, TLI,
-                          LibFunc_Znwm12__hot_cold_t, HotCold);
+    NewCall = emitHotColdNew(CI->getArgOperand(0), B, TLI,
+                             LibFunc_Znwm12__hot_cold_t, HotCold);
     break;
   case LibFunc_Znam12__hot_cold_t:
     if (OptimizeExistingHotColdNew)
-      return emitHotColdNew(CI->getArgOperand(0), B, TLI,
-                            LibFunc_Znam12__hot_cold_t, HotCold);
+      NewCall = emitHotColdNew(CI->getArgOperand(0), B, TLI,
+                               LibFunc_Znam12__hot_cold_t, HotCold);
     break;
   case LibFunc_Znam:
-    return emitHotColdNew(CI->getArgOperand(0), B, TLI,
-                          LibFunc_Znam12__hot_cold_t, HotCold);
+    NewCall = emitHotColdNew(CI->getArgOperand(0), B, TLI,
+                             LibFunc_Znam12__hot_cold_t, HotCold);
     break;
   case LibFunc_ZnwmRKSt9nothrow_t12__hot_cold_t:
     if (OptimizeExistingHotColdNew)
-      return emitHotColdNewNoThrow(
+      NewCall = emitHotColdNewNoThrow(
           CI->getArgOperand(0), CI->getArgOperand(1), B, TLI,
           LibFunc_ZnwmRKSt9nothrow_t12__hot_cold_t, HotCold);
     break;
   case LibFunc_ZnwmRKSt9nothrow_t:
-    return emitHotColdNewNoThrow(CI->getArgOperand(0), CI->getArgOperand(1), B,
-                                 TLI, LibFunc_ZnwmRKSt9nothrow_t12__hot_cold_t,
-                                 HotCold);
+    NewCall = emitHotColdNewNoThrow(
+        CI->getArgOperand(0), CI->getArgOperand(1), B, TLI,
+        LibFunc_ZnwmRKSt9nothrow_t12__hot_cold_t, HotCold);
     break;
   case LibFunc_ZnamRKSt9nothrow_t12__hot_cold_t:
     if (OptimizeExistingHotColdNew)
-      return emitHotColdNewNoThrow(
+      NewCall = emitHotColdNewNoThrow(
           CI->getArgOperand(0), CI->getArgOperand(1), B, TLI,
           LibFunc_ZnamRKSt9nothrow_t12__hot_cold_t, HotCold);
     break;
   case LibFunc_ZnamRKSt9nothrow_t:
-    return emitHotColdNewNoThrow(CI->getArgOperand(0), CI->getArgOperand(1), B,
-                                 TLI, LibFunc_ZnamRKSt9nothrow_t12__hot_cold_t,
-                                 HotCold);
+    NewCall = emitHotColdNewNoThrow(
+        CI->getArgOperand(0), CI->getArgOperand(1), B, TLI,
+        LibFunc_ZnamRKSt9nothrow_t12__hot_cold_t, HotCold);
     break;
   case LibFunc_ZnwmSt11align_val_t12__hot_cold_t:
     if (OptimizeExistingHotColdNew)
-      return emitHotColdNewAligned(
+      NewCall = emitHotColdNewAligned(
           CI->getArgOperand(0), CI->getArgOperand(1), B, TLI,
           LibFunc_ZnwmSt11align_val_t12__hot_cold_t, HotCold);
     break;
   case LibFunc_ZnwmSt11align_val_t:
-    return emitHotColdNewAligned(CI->getArgOperand(0), CI->getArgOperand(1), B,
-                                 TLI, LibFunc_ZnwmSt11align_val_t12__hot_cold_t,
-                                 HotCold);
+    NewCall = emitHotColdNewAligned(
+        CI->getArgOperand(0), CI->getArgOperand(1), B, TLI,
+        LibFunc_ZnwmSt11align_val_t12__hot_cold_t, HotCold);
     break;
   case LibFunc_ZnamSt11align_val_t12__hot_cold_t:
     if (OptimizeExistingHotColdNew)
-      return emitHotColdNewAligned(
+      NewCall = emitHotColdNewAligned(
           CI->getArgOperand(0), CI->getArgOperand(1), B, TLI,
           LibFunc_ZnamSt11align_val_t12__hot_cold_t, HotCold);
     break;
   case LibFunc_ZnamSt11align_val_t:
-    return emitHotColdNewAligned(CI->getArgOperand(0), CI->getArgOperand(1), B,
-                                 TLI, LibFunc_ZnamSt11align_val_t12__hot_cold_t,
-                                 HotCold);
+    NewCall = emitHotColdNewAligned(
+        CI->getArgOperand(0), CI->getArgOperand(1), B, TLI,
+        LibFunc_ZnamSt11align_val_t12__hot_cold_t, HotCold);
     break;
   case LibFunc_ZnwmSt11align_val_tRKSt9nothrow_t12__hot_cold_t:
     if (OptimizeExistingHotColdNew)
-      return emitHotColdNewAlignedNoThrow(
+      NewCall = emitHotColdNewAlignedNoThrow(
           CI->getArgOperand(0), CI->getArgOperand(1), CI->getArgOperand(2), B,
           TLI, LibFunc_ZnwmSt11align_val_tRKSt9nothrow_t12__hot_cold_t,
           HotCold);
     break;
   case LibFunc_ZnwmSt11align_val_tRKSt9nothrow_t:
-    return emitHotColdNewAlignedNoThrow(
+    NewCall = emitHotColdNewAlignedNoThrow(
         CI->getArgOperand(0), CI->getArgOperand(1), CI->getArgOperand(2), B,
         TLI, LibFunc_ZnwmSt11align_val_tRKSt9nothrow_t12__hot_cold_t, HotCold);
     break;
   case LibFunc_ZnamSt11align_val_tRKSt9nothrow_t12__hot_cold_t:
     if (OptimizeExistingHotColdNew)
-      return emitHotColdNewAlignedNoThrow(
+      NewCall = emitHotColdNewAlignedNoThrow(
           CI->getArgOperand(0), CI->getArgOperand(1), CI->getArgOperand(2), B,
           TLI, LibFunc_ZnamSt11align_val_tRKSt9nothrow_t12__hot_cold_t,
           HotCold);
     break;
   case LibFunc_ZnamSt11align_val_tRKSt9nothrow_t:
-    return emitHotColdNewAlignedNoThrow(
+    NewCall = emitHotColdNewAlignedNoThrow(
         CI->getArgOperand(0), CI->getArgOperand(1), CI->getArgOperand(2), B,
         TLI, LibFunc_ZnamSt11align_val_tRKSt9nothrow_t12__hot_cold_t, HotCold);
     break;
   case LibFunc_size_returning_new:
-    return emitHotColdSizeReturningNew(CI->getArgOperand(0), B, TLI,
-                                       LibFunc_size_returning_new_hot_cold,
-                                       HotCold);
+    NewCall = emitHotColdSizeReturningNew(CI->getArgOperand(0), B, TLI,
+                                          LibFunc_size_returning_new_hot_cold,
+                                          HotCold);
     break;
   case LibFunc_size_returning_new_hot_cold:
     if (OptimizeExistingHotColdNew)
-      return emitHotColdSizeReturningNew(CI->getArgOperand(0), B, TLI,
-                                         LibFunc_size_returning_new_hot_cold,
-                                         HotCold);
+      NewCall = emitHotColdSizeReturningNew(CI->getArgOperand(0), B, TLI,
+                                            LibFunc_size_returning_new_hot_cold,
+                                            HotCold);
     break;
   case LibFunc_size_returning_new_aligned:
-    return emitHotColdSizeReturningNewAligned(
+    NewCall = emitHotColdSizeReturningNewAligned(
         CI->getArgOperand(0), CI->getArgOperand(1), B, TLI,
         LibFunc_size_returning_new_aligned_hot_cold, HotCold);
     break;
   case LibFunc_size_returning_new_aligned_hot_cold:
     if (OptimizeExistingHotColdNew)
-      return emitHotColdSizeReturningNewAligned(
+      NewCall = emitHotColdSizeReturningNewAligned(
           CI->getArgOperand(0), CI->getArgOperand(1), B, TLI,
           LibFunc_size_returning_new_aligned_hot_cold, HotCold);
     break;
   default:
     return nullptr;
   }
-  return nullptr;
+
+  if (auto *NewCI = dyn_cast_or_null<Instruction>(NewCall))
+    NewCI->copyMetadata(*CI);
+
+  return NewCall;
 }
 
 //===----------------------------------------------------------------------===//

diff  --git a/llvm/test/Transforms/InstCombine/simplify-libcalls-new.ll b/llvm/test/Transforms/InstCombine/simplify-libcalls-new.ll
index 5a4fb04f5f2c0..2765c75f4d5e0 100644
--- a/llvm/test/Transforms/InstCombine/simplify-libcalls-new.ll
+++ b/llvm/test/Transforms/InstCombine/simplify-libcalls-new.ll
@@ -610,6 +610,16 @@ define void @size_returning_aligned_update_test() {
   ret void
 }
 
+;; Check that !alloc_token is preserved.
+; HOTCOLD-LABEL: @new_alloc_token()
+define void @new_alloc_token() {
+  ;; Attribute cold converted to __hot_cold_t cold value.
+  ; HOTCOLD: @_Znwm12__hot_cold_t(i64 10, i8 [[COLD]]), !alloc_token ![[ALLOC_TOKEN:[0-9]+]]
+  %call = call ptr @_Znwm(i64 10) #0, !alloc_token !0
+  call void @dummy(ptr %call)
+  ret void
+}
+
 ;; So that instcombine doesn't optimize out the call.
 declare void @dummy(ptr)
 
@@ -649,3 +659,6 @@ attributes #5 = { "memprof" = "hot" }
 attributes #8 = { "memprof" = "ambiguous" }
 
 attributes #6 = { nobuiltin allocsize(0) "memprof"="cold" }
+
+; CHECK: [[ALLOC_TOKEN]] = !{!"MyType", i1 false}
+!0 = !{!"MyType", i1 false}


        


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