[PATCH] D25798: Fix regression from my recent GlobalsAA fix.
Eli Friedman via llvm-commits
llvm-commits at lists.llvm.org
Mon Oct 24 14:57:06 PDT 2016
This revision was automatically updated to reflect the committed changes.
Closed by commit rL285034: Fix regression from my recent GlobalsAA fix. (authored by efriedma).
Changed prior to commit:
https://reviews.llvm.org/D25798?vs=75232&id=75651#toc
Repository:
rL LLVM
https://reviews.llvm.org/D25798
Files:
llvm/trunk/lib/Analysis/GlobalsModRef.cpp
llvm/trunk/test/Analysis/GlobalsModRef/global-used-by-global.ll
Index: llvm/trunk/lib/Analysis/GlobalsModRef.cpp
===================================================================
--- llvm/trunk/lib/Analysis/GlobalsModRef.cpp
+++ llvm/trunk/lib/Analysis/GlobalsModRef.cpp
@@ -367,7 +367,9 @@
if (!isa<ConstantPointerNull>(ICI->getOperand(1)))
return true; // Allow comparison against null.
} else if (Constant *C = dyn_cast<Constant>(I)) {
- return C->isConstantUsed();
+ // Ignore constants which don't have any live uses.
+ if (isa<GlobalValue>(C) || C->isConstantUsed())
+ return true;
} else {
return true;
}
Index: llvm/trunk/test/Analysis/GlobalsModRef/global-used-by-global.ll
===================================================================
--- llvm/trunk/test/Analysis/GlobalsModRef/global-used-by-global.ll
+++ llvm/trunk/test/Analysis/GlobalsModRef/global-used-by-global.ll
@@ -0,0 +1,54 @@
+; RUN: opt < %s -globals-aa -gvn -S | FileCheck %s
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+
+ at a = internal global i32* null, align 8
+ at b = global i32** @a, align 8
+ at c = global i32** @a, align 8
+ at d = common global i32 0, align 4
+
+; Make sure we globals-aa doesn't get confused and allow hoisting
+; the load from @a out of the loop.
+
+; CHECK-LABEL: define i32 @main()
+; CHECK: for.body:
+; CHECK-NEXT: %2 = load i32**, i32*** @b, align 8
+; CHECK-NEXT: store i32* @d, i32** %2, align 8
+; CHECK-NEXT: %3 = load i32*, i32** @a, align 8
+; CHECK-NEXT: %cmp1 = icmp ne i32* %3, @d
+; CHECK-NEXT: br i1 %cmp1, label %if.then, label %if.end
+
+define i32 @main() {
+entry:
+ %0 = load i32, i32* @d, align 4
+ br label %for.cond
+
+for.cond: ; preds = %if.end, %entry
+ %1 = phi i32 [ %inc, %if.end ], [ %0, %entry ]
+ %cmp = icmp slt i32 %1, 1
+ br i1 %cmp, label %for.body, label %for.end
+
+for.body: ; preds = %for.cond
+ %2 = load i32**, i32*** @b, align 8
+ store i32* @d, i32** %2, align 8
+ %3 = load i32*, i32** @a, align 8
+ %cmp1 = icmp ne i32* %3, @d
+ br i1 %cmp1, label %if.then, label %if.end
+
+if.then: ; preds = %for.body
+ br label %return
+
+if.end: ; preds = %for.body
+ %4 = load i32, i32* @d, align 4
+ %inc = add nsw i32 %4, 1
+ store i32 %inc, i32* @d, align 4
+ br label %for.cond
+
+for.end: ; preds = %for.cond
+ br label %return
+
+return: ; preds = %for.end, %if.then
+ %retval.0 = phi i32 [ 1, %if.then ], [ 0, %for.end ]
+ ret i32 %retval.0
+}
+
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