From 249ded3fa8884f91fded869fb6e251b8aebb0376 Mon Sep 17 00:00:00 2001 From: Evan Cheng Date: Sat, 23 Feb 2008 03:38:34 +0000 Subject: [PATCH] Rematerialization logic was overly conservative when it comes to loads from fixed stack slots. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47529 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/LiveIntervalAnalysis.cpp | 26 ++++------------- test/CodeGen/X86/2008-02-22-ReMatBug.ll | 49 +++++++++++++++++++++++++++++++++ 2 files changed, 55 insertions(+), 20 deletions(-) create mode 100644 test/CodeGen/X86/2008-02-22-ReMatBug.ll diff --git a/lib/CodeGen/LiveIntervalAnalysis.cpp b/lib/CodeGen/LiveIntervalAnalysis.cpp index a18f36afb7f..2ff8afdeb8c 100644 --- a/lib/CodeGen/LiveIntervalAnalysis.cpp +++ b/lib/CodeGen/LiveIntervalAnalysis.cpp @@ -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) { diff --git a/test/CodeGen/X86/2008-02-22-ReMatBug.ll b/test/CodeGen/X86/2008-02-22-ReMatBug.ll new file mode 100644 index 00000000000..c26c19ee512 --- /dev/null +++ b/test/CodeGen/X86/2008-02-22-ReMatBug.ll @@ -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 ; [#uses=7] + %tmp85 = sub i32 %center_y, %tmp15.reg2mem.0 ; [#uses=2] + %tmp88 = sub i32 %center_x, %tmp15.reg2mem.0 ; [#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 ; [#uses=1] + %tmp100 = sdiv i32 %tmp99, 2 ; [#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 ; [#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 +} -- 2.11.0