diff --git a/llvm/lib/Target/X86/X86InstrInfo.cpp b/llvm/lib/Target/X86/X86InstrInfo.cpp --- a/llvm/lib/Target/X86/X86InstrInfo.cpp +++ b/llvm/lib/Target/X86/X86InstrInfo.cpp @@ -971,18 +971,19 @@ MachineInstr **AndInstr, const TargetRegisterInfo *TRI, bool &NoSignFlag, bool &ClearsOverflowFlag) { - if (CmpValDefInstr.getOpcode() != X86::SUBREG_TO_REG) + if (!(CmpValDefInstr.getOpcode() == X86::SUBREG_TO_REG && + CmpInstr.getOpcode() == X86::TEST64rr) && + !(CmpValDefInstr.getOpcode() == X86::COPY && + CmpInstr.getOpcode() == X86::TEST16rr)) return false; - if (CmpInstr.getOpcode() != X86::TEST64rr) - return false; - - // CmpInstr is a TEST64rr instruction, and `X86InstrInfo::analyzeCompare` - // guarantees that it's analyzable only if two registers are identical. - assert( - (CmpInstr.getOperand(0).getReg() == CmpInstr.getOperand(1).getReg()) && - "CmpInstr is an analyzable TEST64rr, and `X86InstrInfo::analyzeCompare` " - "requires two reg operands are the same."); + // CmpInstr is a TEST16rr/TEST64rr instruction, and + // `X86InstrInfo::analyzeCompare` guarantees that it's analyzable only if two + // registers are identical. + assert((CmpInstr.getOperand(0).getReg() == CmpInstr.getOperand(1).getReg()) && + "CmpInstr is an analyzable TEST16rr/TEST64rr, and " + "`X86InstrInfo::analyzeCompare` requires two reg operands are the" + "same."); // Caller (`X86InstrInfo::optimizeCompareInstr`) guarantees that // `CmpValDefInstr` defines the value that's used by `CmpInstr`; in this case @@ -990,20 +991,37 @@ // redundant. assert( (MRI->getVRegDef(CmpInstr.getOperand(0).getReg()) == &CmpValDefInstr) && - "Caller guarantees that TEST64rr is a user of SUBREG_TO_REG."); + "Caller guarantees that TEST64rr is a user of SUBREG_TO_REG or TEST16rr " + "is a user of COPY sub16bit."); + MachineInstr *VregDefInstr = nullptr; + if (CmpValDefInstr.getOpcode() == X86::COPY && + CmpInstr.getOpcode() == X86::TEST16rr) { + VregDefInstr = MRI->getVRegDef(CmpValDefInstr.getOperand(1).getReg()); + if (!VregDefInstr) + return false; + // We can only remove test when AND32ri or AND64ri32 whose imm can fit 16bit + // size, others 32/64 bit ops would test higher bits which test16rr don't + // want to. + if (!((VregDefInstr->getOpcode() == X86::AND32ri || + VregDefInstr->getOpcode() == X86::AND64ri32) && + isInt<16>(VregDefInstr->getOperand(2).getImm()))) + return false; + } - // As seen in X86 td files, CmpValDefInstr.getOperand(1).getImm() is typically - // 0. - if (CmpValDefInstr.getOperand(1).getImm() != 0) - return false; + if (CmpValDefInstr.getOpcode() == X86::SUBREG_TO_REG && + CmpInstr.getOpcode() == X86::TEST64rr) { + // As seen in X86 td files, CmpValDefInstr.getOperand(1).getImm() is + // typically 0. + if (CmpValDefInstr.getOperand(1).getImm() != 0) + return false; - // As seen in X86 td files, CmpValDefInstr.getOperand(3) is typically - // sub_32bit or sub_xmm. - if (CmpValDefInstr.getOperand(3).getImm() != X86::sub_32bit) - return false; + // As seen in X86 td files, CmpValDefInstr.getOperand(3) is typically + // sub_32bit or sub_xmm. + if (CmpValDefInstr.getOperand(3).getImm() != X86::sub_32bit) + return false; - MachineInstr *VregDefInstr = - MRI->getVRegDef(CmpValDefInstr.getOperand(2).getReg()); + VregDefInstr = MRI->getVRegDef(CmpValDefInstr.getOperand(2).getReg()); + } assert(VregDefInstr && "Must have a definition (SSA)"); @@ -1021,6 +1039,11 @@ // ... // EFLAGS not changed // %extended_reg = subreg_to_reg 0, %reg, %subreg.sub_32bit // test64rr %extended_reg, %extended_reg, implicit-def $eflags + // or + // %reg = and32* ... + // ... // EFLAGS not changed. + // %src_reg = copy %reg.sub_16bit:gr32 + // test16rr %src_reg, %src_reg, implicit-def $eflags // // If subsequent readers use a subset of bits that don't change // after `and*` instructions, it's likely that the test64rr could @@ -4421,10 +4444,15 @@ break; } - // Look back for the following pattern, in which case the test64rr - // instruction could be erased. + // Look back for the following pattern, in which case the + // test16rr/test64rr instruction could be erased. // - // Example: + // Example for test16rr: + // %reg = and32ri %in_reg, 5 + // ... // EFLAGS not changed. + // %src_reg = copy %reg.sub_16bit:gr32 + // test16rr %src_reg, %src_reg, implicit-def $eflags + // Example for test64rr: // %reg = and32ri %in_reg, 5 // ... // EFLAGS not changed. // %src_reg = subreg_to_reg 0, %reg, %subreg.sub_index diff --git a/llvm/test/CodeGen/X86/peephole-test-after-add.mir b/llvm/test/CodeGen/X86/peephole-test-after-add.mir --- a/llvm/test/CodeGen/X86/peephole-test-after-add.mir +++ b/llvm/test/CodeGen/X86/peephole-test-after-add.mir @@ -303,9 +303,8 @@ ; CHECK-NEXT: bb.1.entry: ; CHECK-NEXT: successors: %bb.2(0x55555555), %bb.3(0x2aaaaaab) ; CHECK-NEXT: {{ $}} - ; CHECK-NEXT: [[AND32ri:%[0-9]+]]:gr32 = AND32ri [[COPY1]], 123, implicit-def dead $eflags + ; CHECK-NEXT: [[AND32ri:%[0-9]+]]:gr32 = AND32ri [[COPY1]], 123, implicit-def $eflags ; CHECK-NEXT: [[COPY4:%[0-9]+]]:gr16 = COPY [[AND32ri]].sub_16bit - ; CHECK-NEXT: TEST16rr [[COPY4]], [[COPY4]], implicit-def $eflags ; CHECK-NEXT: JCC_1 %bb.3, 5, implicit $eflags ; CHECK-NEXT: JMP_1 %bb.2 ; CHECK-NEXT: {{ $}}