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https://github.com/c64scene-ar/llvm-6502.git
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fix an x86 fast isel issue where we'd completely give up on folding an address
when we have a global variable base an an index. Instead, just give up on folding the global variable. Before we'd geenrate: _test: ## @test ## BB#0: movq _rtx_length@GOTPCREL(%rip), %rax leaq (%rax), %rax addq %rdi, %rax movzbl (%rax), %eax ret now we generate: _test: ## @test ## BB#0: movq _rtx_length@GOTPCREL(%rip), %rax movzbl (%rax,%rdi), %eax ret The difference is even more significant when there is a scale involved. This fixes rdar://9289558 - total fail with addr mode formation at -O0/x86-64 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129664 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner
parent
685090f598
commit
0a1c997c27
@ -460,91 +460,91 @@ bool X86FastISel::X86SelectAddress(const Value *V, X86AddressMode &AM) {
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// Handle constant address.
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if (const GlobalValue *GV = dyn_cast<GlobalValue>(V)) {
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// Can't handle alternate code models yet.
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// Can't handle alternate code models or TLS yet.
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if (TM.getCodeModel() != CodeModel::Small)
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return false;
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// RIP-relative addresses can't have additional register operands.
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if (Subtarget->isPICStyleRIPRel() &&
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(AM.Base.Reg != 0 || AM.IndexReg != 0))
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return false;
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// Can't handle TLS yet.
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if (const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV))
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if (GVar->isThreadLocal())
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return false;
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// RIP-relative addresses can't have additional register operands, so if
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// we've already folded stuff into the addressing mode, just force the
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// global value into its own register, which we can use as the basereg.
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if (!Subtarget->isPICStyleRIPRel() ||
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(AM.Base.Reg == 0 && AM.IndexReg == 0)) {
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// Okay, we've committed to selecting this global. Set up the address.
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AM.GV = GV;
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// Okay, we've committed to selecting this global. Set up the basic address.
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AM.GV = GV;
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// Allow the subtarget to classify the global.
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unsigned char GVFlags = Subtarget->ClassifyGlobalReference(GV, TM);
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// Allow the subtarget to classify the global.
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unsigned char GVFlags = Subtarget->ClassifyGlobalReference(GV, TM);
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// If this reference is relative to the pic base, set it now.
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if (isGlobalRelativeToPICBase(GVFlags)) {
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// FIXME: How do we know Base.Reg is free??
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AM.Base.Reg = getInstrInfo()->getGlobalBaseReg(FuncInfo.MF);
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}
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// Unless the ABI requires an extra load, return a direct reference to
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// the global.
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if (!isGlobalStubReference(GVFlags)) {
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if (Subtarget->isPICStyleRIPRel()) {
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// Use rip-relative addressing if we can. Above we verified that the
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// base and index registers are unused.
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assert(AM.Base.Reg == 0 && AM.IndexReg == 0);
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AM.Base.Reg = X86::RIP;
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// If this reference is relative to the pic base, set it now.
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if (isGlobalRelativeToPICBase(GVFlags)) {
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// FIXME: How do we know Base.Reg is free??
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AM.Base.Reg = getInstrInfo()->getGlobalBaseReg(FuncInfo.MF);
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}
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AM.GVOpFlags = GVFlags;
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// Unless the ABI requires an extra load, return a direct reference to
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// the global.
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if (!isGlobalStubReference(GVFlags)) {
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if (Subtarget->isPICStyleRIPRel()) {
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// Use rip-relative addressing if we can. Above we verified that the
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// base and index registers are unused.
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assert(AM.Base.Reg == 0 && AM.IndexReg == 0);
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AM.Base.Reg = X86::RIP;
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}
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AM.GVOpFlags = GVFlags;
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return true;
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}
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// Ok, we need to do a load from a stub. If we've already loaded from
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// this stub, reuse the loaded pointer, otherwise emit the load now.
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DenseMap<const Value*, unsigned>::iterator I = LocalValueMap.find(V);
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unsigned LoadReg;
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if (I != LocalValueMap.end() && I->second != 0) {
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LoadReg = I->second;
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} else {
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// Issue load from stub.
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unsigned Opc = 0;
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const TargetRegisterClass *RC = NULL;
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X86AddressMode StubAM;
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StubAM.Base.Reg = AM.Base.Reg;
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StubAM.GV = GV;
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StubAM.GVOpFlags = GVFlags;
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// Prepare for inserting code in the local-value area.
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SavePoint SaveInsertPt = enterLocalValueArea();
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if (TLI.getPointerTy() == MVT::i64) {
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Opc = X86::MOV64rm;
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RC = X86::GR64RegisterClass;
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if (Subtarget->isPICStyleRIPRel())
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StubAM.Base.Reg = X86::RIP;
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} else {
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Opc = X86::MOV32rm;
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RC = X86::GR32RegisterClass;
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}
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LoadReg = createResultReg(RC);
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MachineInstrBuilder LoadMI =
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BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, TII.get(Opc), LoadReg);
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addFullAddress(LoadMI, StubAM);
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// Ok, back to normal mode.
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leaveLocalValueArea(SaveInsertPt);
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// Prevent loading GV stub multiple times in same MBB.
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LocalValueMap[V] = LoadReg;
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}
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// Now construct the final address. Note that the Disp, Scale,
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// and Index values may already be set here.
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AM.Base.Reg = LoadReg;
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AM.GV = 0;
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return true;
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}
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// Ok, we need to do a load from a stub. If we've already loaded from this
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// stub, reuse the loaded pointer, otherwise emit the load now.
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DenseMap<const Value*, unsigned>::iterator I = LocalValueMap.find(V);
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unsigned LoadReg;
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if (I != LocalValueMap.end() && I->second != 0) {
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LoadReg = I->second;
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} else {
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// Issue load from stub.
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unsigned Opc = 0;
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const TargetRegisterClass *RC = NULL;
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X86AddressMode StubAM;
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StubAM.Base.Reg = AM.Base.Reg;
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StubAM.GV = GV;
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StubAM.GVOpFlags = GVFlags;
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// Prepare for inserting code in the local-value area.
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SavePoint SaveInsertPt = enterLocalValueArea();
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if (TLI.getPointerTy() == MVT::i64) {
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Opc = X86::MOV64rm;
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RC = X86::GR64RegisterClass;
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if (Subtarget->isPICStyleRIPRel())
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StubAM.Base.Reg = X86::RIP;
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} else {
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Opc = X86::MOV32rm;
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RC = X86::GR32RegisterClass;
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}
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LoadReg = createResultReg(RC);
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MachineInstrBuilder LoadMI =
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BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, TII.get(Opc), LoadReg);
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addFullAddress(LoadMI, StubAM);
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// Ok, back to normal mode.
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leaveLocalValueArea(SaveInsertPt);
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// Prevent loading GV stub multiple times in same MBB.
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LocalValueMap[V] = LoadReg;
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}
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// Now construct the final address. Note that the Disp, Scale,
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// and Index values may already be set here.
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AM.Base.Reg = LoadReg;
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AM.GV = 0;
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return true;
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}
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// If all else fails, try to materialize the value in a register.
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@ -28,11 +28,11 @@ if.then: ; preds = %entry
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if.end: ; preds = %if.then, %entry
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ret void
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}
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; CHECK: test2:
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; CHECK: movq %rdi, -8(%rsp)
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; CHECK: cmpq $42, -8(%rsp)
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}
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@ -40,8 +40,24 @@ if.end: ; preds = %if.then, %entry
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define i64 @test3() nounwind {
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%A = ptrtoint i32* @G to i64
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ret i64 %A
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}
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; CHECK: test3:
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; CHECK: movq _G@GOTPCREL(%rip), %rax
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; CHECK-NEXT: ret
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}
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; rdar://9289558
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@rtx_length = external global [153 x i8]
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define i32 @test4(i64 %idxprom9) nounwind {
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%arrayidx10 = getelementptr inbounds [153 x i8]* @rtx_length, i32 0, i64 %idxprom9
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%tmp11 = load i8* %arrayidx10, align 1
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%conv = zext i8 %tmp11 to i32
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ret i32 %conv
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; CHECK: test4:
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; CHECK: movq _rtx_length@GOTPCREL(%rip), %rax
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; CHECK-NEXT: movzbl (%rax,%rdi), %eax
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; CHECK-NEXT: ret
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}
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