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Fix regression from my recent GlobalsAA fix.
There are two fixes here: one, AnalyzeUsesOfPointer can't return false until it has checked all the uses of the pointer. Two, if a global uses another global, we have to assume the address of the first global escapes. Fixes https://llvm.org/bugs/show_bug.cgi?id=30707 . Differential Revision: https://reviews.llvm.org/D25798 llvm-svn: 285034
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Eli Friedman
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Oct 24, 2016
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; RUN: opt < %s -globals-aa -gvn -S | FileCheck %s | ||
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target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128" | ||
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@a = internal global i32* null, align 8 | ||
@b = global i32** @a, align 8 | ||
@c = global i32** @a, align 8 | ||
@d = common global i32 0, align 4 | ||
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; Make sure we globals-aa doesn't get confused and allow hoisting | ||
; the load from @a out of the loop. | ||
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; 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 | ||
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define i32 @main() { | ||
entry: | ||
%0 = load i32, i32* @d, align 4 | ||
br label %for.cond | ||
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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 | ||
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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 | ||
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if.then: ; preds = %for.body | ||
br label %return | ||
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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 | ||
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for.end: ; preds = %for.cond | ||
br label %return | ||
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return: ; preds = %for.end, %if.then | ||
%retval.0 = phi i32 [ 1, %if.then ], [ 0, %for.end ] | ||
ret i32 %retval.0 | ||
} | ||
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