[PATCH] D45343: [InstCombine] Always remove null check before free

[Dávid Bolvanský via Phabricator via llvm-commits]

xbolva00 updated this revision to Diff 142111.
xbolva00 added a comment.

Patch updated with suggested changes by @lebedev.ri


https://reviews.llvm.org/D45343

Files:
  lib/Transforms/InstCombine/InstructionCombining.cpp
  test/Transforms/InstCombine/malloc-free-delete.ll


Index: test/Transforms/InstCombine/malloc-free-delete.ll
===================================================================
--- test/Transforms/InstCombine/malloc-free-delete.ll
+++ test/Transforms/InstCombine/malloc-free-delete.ll
@@ -99,7 +99,7 @@
 ;; Then, performing a dead elimination will remove the comparison.
 ;; This is what happens with -O1 and upper.
 ; CHECK-LABEL: @test6(
-define void @test6(i8* %foo) minsize {
+define void @test6(i8* %foo) {
 ; CHECK:  %tobool = icmp eq i8* %foo, null
 ;; Call to free moved
 ; CHECK-NEXT: tail call void @free(i8* %foo)
Index: lib/Transforms/InstCombine/InstructionCombining.cpp
===================================================================
--- lib/Transforms/InstCombine/InstructionCombining.cpp
+++ lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -2327,15 +2327,15 @@
   if (isa<ConstantPointerNull>(Op))
     return eraseInstFromFunction(FI);
 
-  // If we optimize for code size, try to move the call to free before the null
-  // test so that simplify cfg can remove the empty block and dead code
-  // elimination the branch. I.e., helps to turn something like:
+  // Try to move the call to free before the null test so that simplify cfg can
+  // remove the empty block and dead code elimination the branch.
+  // I.e., helps to turn something like:
   // if (foo) free(foo);
   // into
   // free(foo);
-  if (MinimizeSize)
-    if (Instruction *I = tryToMoveFreeBeforeNullTest(FI))
-      return I;
+
+  if (Instruction *I = tryToMoveFreeBeforeNullTest(FI))
+    return I;
 
   return nullptr;
 }


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