[llvm] r209870 - When analyzing params/args for readnone/readonly, don't forget to consider that a pointer argument may be passed through a callsite to the return, and that we may need to analyze it. Fixes a bug reported on llvm-dev: http://lists.cs.uiuc.edu/pipermail/llvmdev/2014-May/073098.html
Nick Lewycky
nicholas at mxc.ca
Thu May 29 19:31:27 PDT 2014
Author: nicholas
Date: Thu May 29 21:31:27 2014
New Revision: 209870
URL: http://llvm.org/viewvc/llvm-project?rev=209870&view=rev
Log:
When analyzing params/args for readnone/readonly, don't forget to consider that a pointer argument may be passed through a callsite to the return, and that we may need to analyze it. Fixes a bug reported on llvm-dev: http://lists.cs.uiuc.edu/pipermail/llvmdev/2014-May/073098.html
Modified:
llvm/trunk/lib/Transforms/IPO/FunctionAttrs.cpp
llvm/trunk/test/Transforms/FunctionAttrs/nocapture.ll
llvm/trunk/test/Transforms/FunctionAttrs/readattrs.ll
Modified: llvm/trunk/lib/Transforms/IPO/FunctionAttrs.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/IPO/FunctionAttrs.cpp?rev=209870&r1=209869&r2=209870&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/IPO/FunctionAttrs.cpp (original)
+++ llvm/trunk/lib/Transforms/IPO/FunctionAttrs.cpp Thu May 29 21:31:27 2014
@@ -449,14 +449,29 @@ determinePointerReadAttrs(Argument *A,
case Instruction::Call:
case Instruction::Invoke: {
+ bool Captures = true;
+
+ if (I->getType()->isVoidTy())
+ Captures = false;
+
+ auto AddUsersToWorklistIfCapturing = [&] {
+ if (Captures)
+ for (Use &UU : I->uses())
+ if (Visited.insert(&UU))
+ Worklist.push_back(&UU);
+ };
+
CallSite CS(I);
- if (CS.doesNotAccessMemory())
+ if (CS.doesNotAccessMemory()) {
+ AddUsersToWorklistIfCapturing();
continue;
+ }
Function *F = CS.getCalledFunction();
if (!F) {
if (CS.onlyReadsMemory()) {
IsRead = true;
+ AddUsersToWorklistIfCapturing();
continue;
}
return Attribute::None;
@@ -471,6 +486,7 @@ determinePointerReadAttrs(Argument *A,
"More params than args in non-varargs call.");
return Attribute::None;
}
+ Captures &= !CS.doesNotCapture(A - B);
if (SCCNodes.count(AI))
continue;
if (!CS.onlyReadsMemory() && !CS.onlyReadsMemory(A - B))
@@ -479,6 +495,7 @@ determinePointerReadAttrs(Argument *A,
IsRead = true;
}
}
+ AddUsersToWorklistIfCapturing();
break;
}
Modified: llvm/trunk/test/Transforms/FunctionAttrs/nocapture.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/FunctionAttrs/nocapture.ll?rev=209870&r1=209869&r2=209870&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/FunctionAttrs/nocapture.ll (original)
+++ llvm/trunk/test/Transforms/FunctionAttrs/nocapture.ll Thu May 29 21:31:27 2014
@@ -68,7 +68,7 @@ define i1* @lookup_bit(i32* %q, i32 %bit
ret i1* %lookup
}
-; CHECK: define i1 @c7(i32* readnone %q, i32 %bitno)
+; CHECK: define i1 @c7(i32* readonly %q, i32 %bitno)
define i1 @c7(i32* %q, i32 %bitno) {
%ptr = call i1* @lookup_bit(i32* %q, i32 %bitno)
%val = load i1* %ptr
Modified: llvm/trunk/test/Transforms/FunctionAttrs/readattrs.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/FunctionAttrs/readattrs.ll?rev=209870&r1=209869&r2=209870&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/FunctionAttrs/readattrs.ll (original)
+++ llvm/trunk/test/Transforms/FunctionAttrs/readattrs.ll Thu May 29 21:31:27 2014
@@ -51,3 +51,17 @@ define void @test6_2(i8** %p, i8* %q) {
define void @test7_1(i32* inalloca %a) {
ret void
}
+
+; CHECK: define i32* @test8_1(i32* readnone %p)
+define i32* @test8_1(i32* %p) {
+entry:
+ ret i32* %p
+}
+
+; CHECK: define void @test8_2(i32* %p)
+define void @test8_2(i32* %p) {
+entry:
+ %call = call i32* @test8_1(i32* %p)
+ store i32 10, i32* %call, align 4
+ ret void
+}
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