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fix PR7876: If ipsccp decides that a function's address is taken 

before it rewrites the code, we need to use that in the post-rewrite pass.

llvm-svn: 110962
This commit is contained in:
Chris Lattner 2010-08-12 22:25:23 +00:00
parent 2b5c1b2516
commit 363226dfe8
2 changed files with 43 additions and 4 deletions
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19
llvm/lib/Transforms/Scalar/SCCP.cpp
View File

@ -1749,6 +1749,13 @@ static bool AddressIsTaken(const GlobalValue *GV) {
bool IPSCCP::runOnModule(Module &M) { bool IPSCCP::runOnModule(Module &M) {
SCCPSolver Solver(getAnalysisIfAvailable<TargetData>()); SCCPSolver Solver(getAnalysisIfAvailable<TargetData>());
// AddressTakenFunctions - This set keeps track of the address-taken functions
// that are in the input. As IPSCCP runs through and simplifies code,
// functions that were address taken can end up losing their
// address-taken-ness. Because of this, we keep track of their addresses from
// the first pass so we can use them for the later simplification pass.
SmallPtrSet<Function*, 32> AddressTakenFunctions;
// Loop over all functions, marking arguments to those with their addresses // Loop over all functions, marking arguments to those with their addresses
// taken or that are external as overdefined. // taken or that are external as overdefined.
// //
@ -1764,9 +1771,13 @@ bool IPSCCP::runOnModule(Module &M) {
// If this function only has direct calls that we can see, we can track its // If this function only has direct calls that we can see, we can track its
// arguments and return value aggressively, and can assume it is not called // arguments and return value aggressively, and can assume it is not called
// unless we see evidence to the contrary. // unless we see evidence to the contrary.
if (F->hasLocalLinkage() && !AddressIsTaken(F)) { if (F->hasLocalLinkage()) {
Solver.AddArgumentTrackedFunction(F); if (AddressIsTaken(F))
continue; AddressTakenFunctions.insert(F);
else {
Solver.AddArgumentTrackedFunction(F);
continue;
}
} }
// Assume the function is called. // Assume the function is called.
@ -1951,7 +1962,7 @@ bool IPSCCP::runOnModule(Module &M) {
continue; continue;
// We can only do this if we know that nothing else can call the function. // We can only do this if we know that nothing else can call the function.
if (!F->hasLocalLinkage() || AddressIsTaken(F)) if (!F->hasLocalLinkage() || AddressTakenFunctions.count(F))
continue; continue;
for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB)

28
llvm/test/Transforms/SCCP/ipsccp-addr-taken.ll Normal file
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@ -0,0 +1,28 @@
; RUN: opt %s -ipsccp -S | FileCheck %s
; PR7876
target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
target triple = "x86_64-apple-darwin10.0.0"
define internal i32 @foo() nounwind noinline ssp {
entry:
ret i32 0
; CHECK: @foo
; CHECK: entry:
; CHECK: ret i32 0
}
declare i32 @bar()
define internal i32 @test(i32 %c) nounwind noinline ssp {
bb:
%tmp1 = icmp ne i32 %c, 0 ; <i1> [#uses=1]
%tmp2 = select i1 %tmp1, i32 ()* @foo, i32 ()* @bar ; <i32 ()*> [#uses=1]
%tmp3 = tail call i32 %tmp2() nounwind ; <i32> [#uses=1]
ret i32 %tmp3
}
define i32 @main() nounwind ssp {
bb:
%tmp = tail call i32 @test(i32 1) ; <i32> [#uses=1]
ret i32 %tmp
}