diff options
author | Eli Friedman <efriedma@codeaurora.org> | 2016-10-24 21:47:44 +0000 |
---|---|---|
committer | Eli Friedman <efriedma@codeaurora.org> | 2016-10-24 21:47:44 +0000 |
commit | 10310d2d1140969e6ebc43d60969747067199478 (patch) | |
tree | 34496afc08c468931b0cec38f5e66eb4b07fa981 | |
parent | 8d980444a43cbe7df3438b98806d4ac38001ebd0 (diff) |
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
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@285034 91177308-0d34-0410-b5e6-96231b3b80d8
-rw-r--r-- | lib/Analysis/GlobalsModRef.cpp | 4 | ||||
-rw-r--r-- | test/Analysis/GlobalsModRef/global-used-by-global.ll | 54 |
2 files changed, 57 insertions, 1 deletions
diff --git a/lib/Analysis/GlobalsModRef.cpp b/lib/Analysis/GlobalsModRef.cpp index a0fa181518d..c955d9dff3a 100644 --- a/lib/Analysis/GlobalsModRef.cpp +++ b/lib/Analysis/GlobalsModRef.cpp @@ -367,7 +367,9 @@ bool GlobalsAAResult::AnalyzeUsesOfPointer(Value *V, 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; } diff --git a/test/Analysis/GlobalsModRef/global-used-by-global.ll b/test/Analysis/GlobalsModRef/global-used-by-global.ll new file mode 100644 index 00000000000..98a8e3a834c --- /dev/null +++ b/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" + +@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 + +; 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 +} + |