https://bugs.llvm.org/show_bug.cgi?id=32363
Bug ID: 32363
Summary: Always inliner should not delete dead calls to
readonly/readnone functions at -O0
Product: libraries
Version: trunk
Hardware: PC
OS: Windows NT
Status: NEW
Severity: enhancement
Priority: P
Component: Interprocedural Optimizations
Assignee: unassignedb...@nondot.org
Reporter: r...@google.com
CC: llvm-bugs@lists.llvm.org
Consider this code:
void readonly(void) __attribute__((__const__));
void readonly(void) {}
void foo(void) { readonly(); }
This code built with 'clang -O0' ends up not calling 'readonly', which is bad
for debugging and dynamic instrumentation tools.
The inliner contains this logic:
// If this call site is dead and it is to a readonly function, we should
// just delete the call instead of trying to inline it, regardless of
// size. This happens because IPSCCP propagates the result out of the
// call and then we're left with the dead call.
if (isInstructionTriviallyDead(CS.getInstruction(), &TLI)) {
DEBUG(dbgs() << " -> Deleting dead call: " << *CS.getInstruction()
<< "\n");
// Update the call graph by deleting the edge from Callee to Caller.
CG[Caller]->removeCallEdgeFor(CS);
CS.getInstruction()->eraseFromParent();
++NumCallsDeleted;
} else {
// We can only inline direct calls to non-declarations.
if (!Callee || Callee->isDeclaration())
continue;
This logic should not be enabled at -O0.
--
You are receiving this mail because:
You are on the CC list for the bug._______________________________________________
llvm-bugs mailing list
llvm-bugs@lists.llvm.org
http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-bugs
