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ARM fix for missing implicit operands on ldmia_ret. 

rdar://10005094: miscompile of 176.gcc

llvm-svn: 138568
This commit is contained in:
Andrew Trick 2011-08-25 17:50:53 +00:00
parent 73d5f67f5a
commit 6446bf780a
2 changed files with 103 additions and 1 deletions
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4
llvm/lib/Target/ARM/ARMFrameLowering.cpp
View File

@ -646,8 +646,10 @@ void ARMFrameLowering::emitPopInst(MachineBasicBlock &MBB,
.addReg(ARM::SP));
for (unsigned i = 0, e = Regs.size(); i < e; ++i)
MIB.addReg(Regs[i], getDefRegState(true));
if (DeleteRet)
if (DeleteRet) {
MIB->copyImplicitOps(&*MI);
MI->eraseFromParent();
}
MI = MIB;
} else if (Regs.size() == 1) {
// If we adjusted the reg to PC from LR above, switch it back here. We

100
llvm/test/CodeGen/ARM/2011-08-25-ldmia_ret.ll Normal file
View File

@ -0,0 +1,100 @@
; RUN: llc < %s -mtriple=thumbv7-apple-darwin -mcpu=cortex-a9 | FileCheck %s
; Test that ldmia_ret preserves implicit operands for return values.
;
; This CFG is reduced from a benchmark miscompile. With current
; if-conversion heuristics, one of the return paths is if-converted
; into sw.bb18 resulting in an ldmia_ret in the middle of the
; block. The postra scheduler needs to know that the return implicitly
; uses the return register, otherwise its antidep breaker scavenges
; the register in order to hoist the constant load required to test
; the switch.
declare i32 @getint()
declare i1 @getbool()
declare void @foo(i32)
declare i32 @bar(i32)
define i32 @test(i32 %in1, i32 %in2) nounwind {
entry:
%call = tail call zeroext i1 @getbool() nounwind
br i1 %call, label %sw.bb18, label %sw.bb2
sw.bb2: ; preds = %entry
%cmp = tail call zeroext i1 @getbool() nounwind
br i1 %cmp, label %sw.epilog58, label %land.lhs.true
land.lhs.true: ; preds = %sw.bb2
%cmp13 = tail call zeroext i1 @getbool() nounwind
br i1 %cmp13, label %if.then, label %sw.epilog58
if.then: ; preds = %land.lhs.true
tail call void @foo(i32 %in1) nounwind
br label %sw.epilog58
; load the return value
; CHECK: movs [[RRET:r.]], #2
; hoist the switch constant without clobbering RRET
; CHECK: movw
; CHECK-NOT: [[RRET]]
; CHECK: , #63707
; CHECK-NOT: [[RRET]]
; CHECK: tst
; If-convert the return
; CHECK: it ne
; Fold the CSR+return into a pop
; CHECK: popne {r4, r5, r7, pc}
sw.bb18:
%call20 = tail call i32 @bar(i32 %in2) nounwind
switch i32 %call20, label %sw.default56 [
i32 168, label %sw.bb21
i32 165, label %sw.bb21
i32 261, label %sw.epilog58
i32 188, label %sw.epilog58
i32 187, label %sw.epilog58
i32 186, label %sw.epilog58
i32 185, label %sw.epilog58
i32 184, label %sw.epilog58
i32 175, label %sw.epilog58
i32 174, label %sw.epilog58
i32 173, label %sw.epilog58
i32 172, label %sw.epilog58
i32 171, label %sw.epilog58
i32 167, label %sw.epilog58
i32 166, label %sw.epilog58
i32 164, label %sw.epilog58
i32 163, label %sw.epilog58
i32 161, label %sw.epilog58
i32 160, label %sw.epilog58
i32 -1, label %sw.bb33
]
sw.bb21: ; preds = %sw.bb18, %sw.bb18
tail call void @foo(i32 %in2) nounwind
%call28 = tail call i32 @getint() nounwind
%tobool = icmp eq i32 %call28, 0
br i1 %tobool, label %if.then29, label %sw.epilog58
if.then29: ; preds = %sw.bb21
tail call void @foo(i32 %in2) nounwind
br label %sw.epilog58
sw.bb33: ; preds = %sw.bb18
%cmp42 = tail call zeroext i1 @getbool() nounwind
br i1 %cmp42, label %sw.default56, label %land.lhs.true44
land.lhs.true44: ; preds = %sw.bb33
%call50 = tail call i32 @getint() nounwind
%cmp51 = icmp slt i32 %call50, 0
br i1 %cmp51, label %if.then53, label %sw.default56
if.then53: ; preds = %land.lhs.true44
tail call void @foo(i32 %in2) nounwind
br label %sw.default56
sw.default56: ; preds = %sw.bb33, %land.lhs.true44, %if.then53, %sw.bb18
br label %sw.epilog58
sw.epilog58:
%retval.0 = phi i32 [ 4, %sw.default56 ], [ 2, %sw.bb21 ], [ 2, %if.then29 ], [ 2, %sw.bb18 ], [ 2, %sw.bb18 ], [ 2, %sw.bb18 ], [ 2, %sw.bb18 ], [ 2, %sw.bb18 ], [ 2, %sw.bb18 ], [ 2, %sw.bb18 ], [ 2, %sw.bb18 ], [ 2, %sw.bb18 ], [ 2, %sw.bb18 ], [ 2, %sw.bb18 ], [ 2, %sw.bb18 ], [ 2, %sw.bb18 ], [ 2, %sw.bb18 ], [ 2, %sw.bb18 ], [ 2, %sw.bb18 ], [ 2, %sw.bb18 ], [ 2, %sw.bb2 ], [ 2, %land.lhs.true ], [ 2, %if.then ]
ret i32 %retval.0
}