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Temporarily revert "[PowerPC] Allow tail calls of fastcc functions from C CallingConv functions." 

It is causing sanitizer failures on llvm tests in a bootstrapped compiler. No bot link since it's currently down, but following up to get the bot up.

This reverts commit r319218.

llvm-svn: 320106
This commit is contained in:
Eric Christopher 2017-12-07 22:26:19 +00:00
parent b0c97e566f
commit a469acac03
2 changed files with 8 additions and 13 deletions
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15
llvm/lib/Target/PowerPC/PPCISelLowering.cpp
View File

@ -4397,18 +4397,13 @@ hasSameArgumentList(const Function *CallerFn, ImmutableCallSite CS) {
static bool
areCallingConvEligibleForTCO_64SVR4(CallingConv::ID CallerCC,
CallingConv::ID CalleeCC) {
// tail calls are possible with fastcc and ccc.
auto isTailCallableCC = [] (CallingConv::ID CC){
return CC == CallingConv::C || CC == CallingConv::Fast;
};
if (!isTailCallableCC(CallerCC) || !isTailCallableCC(CalleeCC))
// Tail or Sibling call optimization (TCO/SCO) needs callee and caller to
// have the same calling convention.
if (CallerCC != CalleeCC)
return false;
// We can safely tail call both fastcc and ccc callees from a c calling
// convention caller. If the caller is fastcc, we may have less stack space
// then a non-fastcc caller with the same signature so disable tail-calls in
// that case.
return CallerCC == CallingConv::C || CallerCC == CalleeCC;
// Tail or Sibling calls can be done with fastcc/ccc.
return (CallerCC == CallingConv::Fast || CallerCC == CallingConv::C);
}
bool

6
llvm/test/CodeGen/PowerPC/duplicate-returns-for-tailcall.ll
View File

@ -42,10 +42,10 @@ if.end4: ; preds = %if.end
if.then6: ; preds = %if.end4
%call7 = tail call fastcc signext i32 @call3(i32 signext %a, i32 signext %b, i32 signext %c)
br label %return
; tail calling a fastcc function from a ccc function is supported.
; No duplication here because the calling convention mismatch means we won't tail-call
; CHECK_LABEL: if.then13:
; CHECK: %[[T2:[a-zA-Z0-9]+]] = tail call fastcc signext i32 @call3
; CHECK-NEXT: ret i32 %[[T2]]
; CHECK: tail call fastcc signext i32 @call3
; CHECK-NEXT: br
return: ; preds = %if.end4, %if.then6, %if.then2, %if.then
%retval.0 = phi i32 [ %call, %if.then ], [ %call3, %if.then2 ], [ %call7, %if.then6 ], [ %c, %if.end4 ]