[llvm] b07aab8 - [GlobalOpt] Iterate over replaced values deterministically to constprop

[Arthur Eubanks via llvm-commits]

Author: Arthur Eubanks
Date: 2022-05-02T09:43:20-07:00
New Revision: b07aab8fc1088ef66ecbe2befc3ef7e3936a390e

URL: https://github.com/llvm/llvm-project/commit/b07aab8fc1088ef66ecbe2befc3ef7e3936a390e
DIFF: https://github.com/llvm/llvm-project/commit/b07aab8fc1088ef66ecbe2befc3ef7e3936a390e.diff

LOG: [GlobalOpt] Iterate over replaced values deterministically to constprop

If there are pre-existing dead instructions, the order we visit replaced
values can cause us sometimes to not delete dead instructions.

The added test non-deterministically failed without the change.

Added: 
    llvm/test/Transforms/GlobalOpt/malloc-promote-6.ll

Modified: 
    llvm/lib/Transforms/IPO/GlobalOpt.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Transforms/IPO/GlobalOpt.cpp b/llvm/lib/Transforms/IPO/GlobalOpt.cpp
index 72b94cda01bf4..157cb27ec96f5 100644
--- a/llvm/lib/Transforms/IPO/GlobalOpt.cpp
+++ b/llvm/lib/Transforms/IPO/GlobalOpt.cpp
@@ -17,6 +17,7 @@
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/SetVector.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/ADT/Twine.h"
 #include "llvm/ADT/iterator_range.h"
@@ -904,7 +905,7 @@ OptimizeGlobalAddressOfAllocation(GlobalVariable *GV, CallInst *CI,
     }
   }
 
-  SmallPtrSet<Constant *, 1> RepValues;
+  SmallSetVector<Constant *, 1> RepValues;
   RepValues.insert(NewGV);
 
   // If there is a comparison against null, we will insert a global bool to

diff  --git a/llvm/test/Transforms/GlobalOpt/malloc-promote-6.ll b/llvm/test/Transforms/GlobalOpt/malloc-promote-6.ll
new file mode 100644
index 0000000000000..f35e1aea60158
--- /dev/null
+++ b/llvm/test/Transforms/GlobalOpt/malloc-promote-6.ll
@@ -0,0 +1,30 @@
+; RUN: opt -passes=globalopt -S < %s | FileCheck %s
+
+; CHECK-NOT: @global
+
+ at global = internal global i8* null
+ at llvm.global_ctors = appending global [1 x { i32, void ()*, i8* }] [{ i32, void ()*, i8* } { i32 65535, void ()* @zot, i8* null }]
+
+declare i8* @_Znwm(i64)
+
+define internal void @widget() {
+  %tmp = tail call i8* @_Znwm(i64 0)
+  %tmp2 = getelementptr inbounds i8, i8* %tmp, i64 0
+  store i8* %tmp, i8** @global, align 8
+  call void @baz(void ()* @spam)
+  ret void
+}
+
+define internal void @spam() {
+  %tmp = load i8*, i8** @global, align 8
+  %tmp2 = getelementptr inbounds i8, i8* %tmp, i64 0
+  ret void
+}
+
+define internal void @zot() {
+  call void @baz(void ()* @widget)
+  ret void
+}
+
+declare void @baz(void ()*)
+