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Rematerialization logic was overly conservative when it comes to loads from fixed stack slots.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47529 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evan Cheng 2008-02-23 03:38:34 +00:00
parent aaa1d4265e
commit 249ded3fa8
2 changed files with 55 additions and 20 deletions
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26
lib/CodeGen/LiveIntervalAnalysis.cpp
View File

@ -646,27 +646,9 @@ bool LiveIntervals::isReMaterializable(const LiveInterval &li,
int FrameIdx = 0;
if (tii_->isLoadFromStackSlot(MI, FrameIdx) &&
mf_->getFrameInfo()->isImmutableObjectIndex(FrameIdx)) {
// This is a load from fixed stack slot. It can be rematerialized unless
// it's re-defined by a two-address instruction.
isLoad = true;
for (LiveInterval::const_vni_iterator i = li.vni_begin(), e = li.vni_end();
i != e; ++i) {
const VNInfo *VNI = *i;
if (VNI == ValNo)
continue;
unsigned DefIdx = VNI->def;
if (DefIdx == ~1U)
continue; // Dead val#.
MachineInstr *DefMI = (DefIdx == ~0u)
? NULL : getInstructionFromIndex(DefIdx);
if (DefMI && DefMI->isRegReDefinedByTwoAddr(li.reg)) {
isLoad = false;
return false;
}
}
mf_->getFrameInfo()->isImmutableObjectIndex(FrameIdx))
// This is a load from fixed stack slot. It can be rematerialized.
return true;
}
if (tii_->isTriviallyReMaterializable(MI)) {
isLoad = TID.isSimpleLoad();
@ -754,6 +736,10 @@ bool LiveIntervals::tryFoldMemoryOperand(MachineInstr* &MI,
FoldOps.push_back(OpIdx);
}
// Can't fold a load from fixed stack slot into a two address instruction.
if (isSS && DefMI && (MRInfo & VirtRegMap::isMod))
return false;
MachineInstr *fmi = isSS ? tii_->foldMemoryOperand(*mf_, MI, FoldOps, Slot)
: tii_->foldMemoryOperand(*mf_, MI, FoldOps, DefMI);
if (fmi) {

49
test/CodeGen/X86/2008-02-22-ReMatBug.ll Normal file
View File

@ -0,0 +1,49 @@
; RUN: llvm-as < %s | llc -march=x86 -stats |& grep {Number of re-materialization} | grep 3
; rdar://5761454
%struct.quad_struct = type { i32, i32, %struct.quad_struct*, %struct.quad_struct*, %struct.quad_struct*, %struct.quad_struct*, %struct.quad_struct* }
define fastcc %struct.quad_struct* @MakeTree(i32 %size, i32 %center_x, i32 %center_y, i32 %lo_proc, i32 %hi_proc, %struct.quad_struct* %parent, i32 %ct, i32 %level) nounwind {
entry:
br i1 true, label %bb43.i, label %bb.i
bb.i: ; preds = %entry
ret %struct.quad_struct* null
bb43.i: ; preds = %entry
br i1 true, label %CheckOutside.exit40.i, label %bb11.i38.i
bb11.i38.i: ; preds = %bb43.i
ret %struct.quad_struct* null
CheckOutside.exit40.i: ; preds = %bb43.i
br i1 true, label %CheckOutside.exit30.i, label %bb11.i28.i
bb11.i28.i: ; preds = %CheckOutside.exit40.i
ret %struct.quad_struct* null
CheckOutside.exit30.i: ; preds = %CheckOutside.exit40.i
br i1 true, label %CheckOutside.exit20.i, label %bb11.i18.i
bb11.i18.i: ; preds = %CheckOutside.exit30.i
ret %struct.quad_struct* null
CheckOutside.exit20.i: ; preds = %CheckOutside.exit30.i
br i1 true, label %bb34, label %bb11.i8.i
bb11.i8.i: ; preds = %CheckOutside.exit20.i
ret %struct.quad_struct* null
bb34: ; preds = %CheckOutside.exit20.i
%tmp15.reg2mem.0 = sdiv i32 %size, 2 ; <i32> [#uses=7]
%tmp85 = sub i32 %center_y, %tmp15.reg2mem.0 ; <i32> [#uses=2]
%tmp88 = sub i32 %center_x, %tmp15.reg2mem.0 ; <i32> [#uses=2]
%tmp92 = tail call fastcc %struct.quad_struct* @MakeTree( i32 %tmp15.reg2mem.0, i32 %tmp88, i32 %tmp85, i32 0, i32 %hi_proc, %struct.quad_struct* null, i32 2, i32 0 ) nounwind ; <%struct.quad_struct*> [#uses=0]
%tmp99 = add i32 0, %hi_proc ; <i32> [#uses=1]
%tmp100 = sdiv i32 %tmp99, 2 ; <i32> [#uses=1]
%tmp110 = tail call fastcc %struct.quad_struct* @MakeTree( i32 %tmp15.reg2mem.0, i32 0, i32 %tmp85, i32 0, i32 %tmp100, %struct.quad_struct* null, i32 3, i32 0 ) nounwind ; <%struct.quad_struct*> [#uses=0]
%tmp122 = add i32 %tmp15.reg2mem.0, %center_y ; <i32> [#uses=2]
%tmp129 = tail call fastcc %struct.quad_struct* @MakeTree( i32 %tmp15.reg2mem.0, i32 0, i32 %tmp122, i32 0, i32 0, %struct.quad_struct* null, i32 1, i32 0 ) nounwind ; <%struct.quad_struct*> [#uses=0]
%tmp147 = tail call fastcc %struct.quad_struct* @MakeTree( i32 %tmp15.reg2mem.0, i32 %tmp88, i32 %tmp122, i32 %lo_proc, i32 0, %struct.quad_struct* null, i32 0, i32 0 ) nounwind ; <%struct.quad_struct*> [#uses=0]
unreachable
}