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Fix PR6300. 

A virtual register can be used before it is defined in the same MBB if the MBB
is part of a loop. Teach the implicit-def pass about this case.

llvm-svn: 96279
This commit is contained in:
Jakob Stoklund Olesen 2010-02-15 22:03:29 +00:00
parent 3996e249ed
commit 2988d573e5
2 changed files with 82 additions and 3 deletions
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5
llvm/lib/CodeGen/ProcessImplicitDefs.cpp
View File

@ -205,10 +205,9 @@ bool ProcessImplicitDefs::runOnMachineFunction(MachineFunction &fn) {
// Process each use instruction once.
for (MachineRegisterInfo::use_iterator UI = mri_->use_begin(Reg),
UE = mri_->use_end(); UI != UE; ++UI) {
MachineInstr *RMI = &*UI;
MachineBasicBlock *RMBB = RMI->getParent();
if (RMBB == MBB)
if (UI.getOperand().isUndef())
continue;
MachineInstr *RMI = &*UI;
if (ModInsts.insert(RMI))
RUses.push_back(RMI);
}

80
llvm/test/CodeGen/X86/2010-02-15-ImplicitDefBug.ll Normal file
View File

@ -0,0 +1,80 @@
; RUN: llc < %s > %t
; PR6300
target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:32:32-n8:16:32"
target triple = "i386-pc-linux-gnu"
; When the "154" loops back onto itself, it defines a register after using it.
; The first value of the register is implicit-def.
%"struct location_chain_def" = type { %"struct location_chain_def"*, %"struct rtx_def"*, %"struct rtx_def"*, i32 }
%"struct real_value" = type { i32, [5 x i32] }
%"struct rtx_def" = type { i16, i8, i8, %"union u" }
%"union u" = type { %"struct real_value" }
define i32 @variable_union(i8** nocapture %slot, i8* nocapture %data) nounwind {
entry:
br i1 undef, label %"4.thread", label %"3"
"4.thread": ; preds = %entry
unreachable
"3": ; preds = %entry
br i1 undef, label %"19", label %"20"
"19": ; preds = %"3"
unreachable
"20": ; preds = %"3"
br i1 undef, label %"56.preheader", label %dv_onepart_p.exit
dv_onepart_p.exit: ; preds = %"20"
unreachable
"56.preheader": ; preds = %"20"
br label %"56"
"50": ; preds = %"57"
br label %"56"
"56": ; preds = %"50", %"56.preheader"
br i1 undef, label %"57", label %"58"
"57": ; preds = %"56"
br i1 undef, label %"50", label %"58"
"58": ; preds = %"57", %"56"
br i1 undef, label %"62", label %"63"
"62": ; preds = %"58"
unreachable
"63": ; preds = %"58"
br i1 undef, label %"67", label %"66"
"66": ; preds = %"63"
br label %"67"
"67": ; preds = %"66", %"63"
br label %"68"
"68": ; preds = %"161", %"67"
br i1 undef, label %"153", label %"161"
"153": ; preds = %"68"
br i1 undef, label %"160", label %bb.nph46
bb.nph46: ; preds = %"153"
br label %"154"
"154": ; preds = %"154", %bb.nph46
%0 = phi %"struct location_chain_def"** [ undef, %bb.nph46 ], [ %1, %"154" ] ; <%"struct location_chain_def"**> [#uses=1]
%1 = bitcast i8* undef to %"struct location_chain_def"** ; <%"struct location_chain_def"**> [#uses=1]
store %"struct location_chain_def"* undef, %"struct location_chain_def"** %0, align 4
br i1 undef, label %"160", label %"154"
"160": ; preds = %"154", %"153"
br label %"161"
"161": ; preds = %"160", %"68"
br label %"68"
}