[X86][Btver2] Fix latency and throughput of CMPXCHG instructions.

[andreadb]

Summary

On Jaguar, CMPXCHG has a latency of 11cy, and a maximum throughput of 0.33 IPC. Throughput is superiorly limited to 0.33 because of the implicit in/out dependency on register EAX. In the case of repeated non-atomic CMPXCHG with the same memory location, store-to-load forwarding occurs and values for sequent loads are quickly forwarded from the store buffer.

Interestingly, the functionality in LLVM that computes the reciprocal throughput doesn't seem to know about RMW instructions. That functionality only looks at the "consumed resource cycles" for the throughput computation. It should be fixed/improved by a future patch. In particular, for RMW instructions, that logic should also take into account for the write latency of in/out register operands.

An atomic CMPXCHG has a latency of ~17cy. Throughput is also limited to ~17cy/inst due to cache locking, which prevents other memory uOPs to start executing before the "lock releasing" store uOP.

CMPXCHG8rr and CMPXCHG8rm are treated specially because they decode to one less macro opcode. Their latency tend to be the same as the other RR/RM variants. RR variants are relatively fast 3cy (but still microcoded - 5 macro opcodes).

The two new hasLockPrefix() functions are used by the btver2 scheduling model check if a MCInst/MachineInst has a LOCK prefix. Calls to hasLockPrefix() have been encoded in predicates of variant scheduling classes that describe lat/thr of CMPXCHG.

Let me know if okay to commit.

[lebedev.ri]

test/tools/llvm-mca/X86/BtVer2/resources-cmpxchg.s

8

Can these test updates be propagated to every resources-cmpxchg.s please?

[andreadb]

test/tools/llvm-mca/X86/BtVer2/resources-cmpxchg.s

8

Sure. I am going to do this as a NFC. Then I update this patch.

[andreadb]

Address review comment.

Test files have been updated at r369279.

[RKSimon]

test/tools/llvm-mca/X86/BtVer2/resources-cmpxchg.s

48

Only the 8b/16b ops should be in resources-cmpxchg.s, the rest should be in resources-x86_64.s - the non-lock ops are already there. Ideally we'd have coverage for all the other lock ops (ADD, ADC, etc.) but I'm happy to deal with that later.

[andreadb]

Patch updated.

CMPXCHG have been moved to resources-x86_64.s as requested by @RKSimon .

Added missing scheduling information for CMPXCHG8B and CMPXCHG16B.
CMPXCHG8B is 11cy and unfortunately doesn't seem to benefit from store-to-load forwarding. That means, throughput is clearly limited by the in/out dependency on GPR registers. The uOP composition is sadly unknown (due to the lack of PMCs for the Integer pipes). I have reused the same mix of consumed resource from the other CMPXCHG instructions for CMPXCHG8B too.

LOCK CMPXCHG8B is instead 18cycles.

CMPXCHG16B is 32cycles. Up to 38cycles when the LOCK prefix is specified. Due to the in/out dependencies, throughput is limited to 1 instruction every 32 (or 38) cycles dependeing on whether the LOCK prefix is specified or not.
I wouldn't be surprised if the microcode for CMPXCHG16B is similar to 2x microcode from CMPXCHG8B. So, I have speculatively set the JALU01 consumption to 2x the resource cycles used for CMPXCHG8B.

[RKSimon]

LGTM - thanks!

lib/Target/X86/MCTargetDesc/X86MCTargetDesc.h

 
 namespace X86_MC {
 std::string ParseX86Triple(const Triple &TT);
 
 unsigned getDwarfRegFlavour(const Triple &TT, bool isEH);
 
 void initLLVMToSEHAndCVRegMapping(MCRegisterInfo *MRI);
 
+
+/// Returns true if this instruction has a LOCK prefix.
+bool hasLockPrefix(const MCInst &MI);
+
 /// Create a X86 MCSubtargetInfo instance. This is exposed so Asm parser, etc.
 /// do not need to go through TargetRegistry.
 MCSubtargetInfo *createX86MCSubtargetInfo(const Triple &TT, StringRef CPU,
                                           StringRef FS);
 }
 
 MCCodeEmitter *createX86MCCodeEmitter(const MCInstrInfo &MCII,
                                       const MCRegisterInfo &MRI,

lib/Target/X86/MCTargetDesc/X86MCTargetDesc.cpp

unsigned X86_MC::getDwarfRegFlavour(const Triple &TT, bool isEH) {
   if (TT.isOSDarwin())
     return isEH ? DWARFFlavour::X86_32_DarwinEH : DWARFFlavour::X86_32_Generic;
   if (TT.isOSCygMing())
     // Unsupported by now, just quick fallback
     return DWARFFlavour::X86_32_Generic;
   return DWARFFlavour::X86_32_Generic;
 }
 
+bool X86_MC::hasLockPrefix(const MCInst &MI) {
+  return MI.getFlags() & X86::IP_HAS_LOCK;
+}
+
 void X86_MC::initLLVMToSEHAndCVRegMapping(MCRegisterInfo *MRI) {
   // FIXME: TableGen these.
   for (unsigned Reg = X86::NoRegister + 1; Reg < X86::NUM_TARGET_REGS; ++Reg) {
     unsigned SEH = MRI->getEncodingValue(Reg);
     MRI->mapLLVMRegToSEHReg(Reg, SEH);
   }
 
   // Mapping from CodeView to MC register id.

lib/Target/X86/X86InstrInfo.h

public:
   MachineBasicBlock::iterator
   insertOutlinedCall(Module &M, MachineBasicBlock &MBB,
                      MachineBasicBlock::iterator &It, MachineFunction &MF,
                      const outliner::Candidate &C) const override;
 
 #define GET_INSTRINFO_HELPER_DECLS
 #include "X86GenInstrInfo.inc"
 
+  static bool hasLockPrefix(const MachineInstr &MI) {
+    return MI.getDesc().TSFlags & X86II::LOCK;
+  }
+
   Optional<ParamLoadedValue>
   describeLoadedValue(const MachineInstr &MI) const override;
 
 protected:
   /// Commutes the operands in the given instruction by changing the operands
   /// order and/or changing the instruction's opcode and/or the immediate value
   /// operand.
   ///

lib/Target/X86/X86SchedPredicates.td

def IsSETAr_Or_SETBEr : CheckAny<[
   CheckImmOperand_s<1, "X86::COND_A">,
   CheckImmOperand_s<1, "X86::COND_BE">
 ]>;
 
 def IsSETAm_Or_SETBEm : CheckAny<[
   CheckImmOperand_s<5, "X86::COND_A">,
   CheckImmOperand_s<5, "X86::COND_BE">
 ]>;
+
+// A predicate used to check if an instruction has a LOCK prefix.
+def CheckLockPrefix : CheckFunctionPredicate<
+  "X86_MC::hasLockPrefix",
+  "X86InstrInfo::hasLockPrefix"
+>;
+
+def IsRegRegCompareAndSwap_8 : CheckOpcode<[ CMPXCHG8rr ]>;
+
+def IsRegMemCompareAndSwap_8 : CheckOpcode<[
+  LCMPXCHG8, CMPXCHG8rm
+]>;
+
+def IsRegRegCompareAndSwap_16_32_64  : CheckOpcode<[
+  CMPXCHG16rr, CMPXCHG32rr, CMPXCHG64rr
+]>;
+
+def IsRegMemCompareAndSwap_16_32_64  : CheckOpcode<[
+  CMPXCHG16rm, CMPXCHG32rm, CMPXCHG64rm,
+  CMPXCHG8B, CMPXCHG16B,
+  LCMPXCHG16, LCMPXCHG32, LCMPXCHG64,
+  LCMPXCHG8B, LCMPXCHG16B
+]>;
+
+def IsRegMemCompareAndSwap  : CheckOpcode<
+  !listconcat(
+    IsRegMemCompareAndSwap_8.ValidOpcodes,
+    IsRegMemCompareAndSwap_16_32_64.ValidOpcodes
+  )>;
+
+def IsRegRegCompareAndSwap  : CheckOpcode<
+  !listconcat(
+    IsRegRegCompareAndSwap_8.ValidOpcodes,
+    IsRegRegCompareAndSwap_16_32_64.ValidOpcodes
+  )>;
+
+def IsAtomicCompareAndSwap_8 : CheckAll<[
+  CheckLockPrefix,
+  IsRegMemCompareAndSwap_8
+]>;
+
+def IsAtomicCompareAndSwap : CheckAll<[
+  CheckLockPrefix,
+  IsRegMemCompareAndSwap
+]>;

lib/Target/X86/X86ScheduleBtVer2.td

 
 ////////////////////////////////////////////////////////////////////////////////
 // Arithmetic.
 ////////////////////////////////////////////////////////////////////////////////
 
 defm : JWriteResIntPair<WriteALU,    [JALU01], 1>;
 defm : JWriteResIntPair<WriteADC,    [JALU01], 1, [2]>;
 
-defm : X86WriteRes<WriteBSWAP32, [JALU01], 1, [1], 1>;
-defm : X86WriteRes<WriteBSWAP64, [JALU01], 1, [1], 1>;
-defm : X86WriteRes<WriteCMPXCHG,[JALU01], 1, [1], 1>;
-defm : X86WriteRes<WriteCMPXCHGRMW,[JALU01, JSAGU, JLAGU], 4, [1, 1, 1], 2>;
+defm : X86WriteRes<WriteBSWAP32,     [JALU01], 1, [1], 1>;
+defm : X86WriteRes<WriteBSWAP64,     [JALU01], 1, [1], 1>;
+defm : X86WriteRes<WriteCMPXCHG,     [JALU01], 3, [3], 5>;
+defm : X86WriteRes<WriteCMPXCHGRMW,  [JALU01, JSAGU, JLAGU], 11, [3, 1, 1], 6>;
 defm : X86WriteRes<WriteXCHG,        [JALU01], 1, [1], 1>;
 
 defm : JWriteResIntPair<WriteIMul8,     [JALU1, JMul], 3, [1, 1], 2>;
 defm : JWriteResIntPair<WriteIMul16,    [JALU1, JMul], 3, [1, 1], 2>;
 defm : JWriteResIntPair<WriteIMul16Imm, [JALU1, JMul], 3, [1, 1], 2>;
 defm : JWriteResIntPair<WriteIMul16Reg, [JALU1, JMul], 3, [1, 1], 2>;
 defm : JWriteResIntPair<WriteIMul32,    [JALU1, JMul], 3, [1, 1], 2>;
 defm : JWriteResIntPair<WriteIMul32Imm, [JALU1, JMul], 3, [1, 1], 2>;

 def : WriteRes<WriteSystem,     [JALU01]> { let Latency = 100; }
 def : WriteRes<WriteMicrocoded, [JALU01]> { let Latency = 100; }
 def : WriteRes<WriteFence,  [JSAGU]>;
 
 // Nops don't have dependencies, so there's no actual latency, but we set this
 // to '1' to tell the scheduler that the nop uses an ALU slot for a cycle.
 def : WriteRes<WriteNop, [JALU01]> { let Latency = 1; }
 
+def JWriteCMPXCHG8rr : SchedWriteRes<[JALU01]> {
+  let Latency = 3;
+  let ResourceCycles = [3];
+  let NumMicroOps = 3;
+}
+
+def JWriteLOCK_CMPXCHG8rm : SchedWriteRes<[JALU01, JLAGU, JSAGU]> {
+  let Latency = 16;
+  let ResourceCycles = [3,16,16];
+  let NumMicroOps = 5;
+}
+
+def JWriteLOCK_CMPXCHGrm : SchedWriteRes<[JALU01, JLAGU, JSAGU]> {
+  let Latency = 17;
+  let ResourceCycles = [3,17,17];
+  let NumMicroOps = 6;
+}
+
+def JWriteCMPXCHG8rm : SchedWriteRes<[JALU01, JLAGU, JSAGU]> {
+  let Latency = 11;
+  let ResourceCycles = [3,1,1];
+  let NumMicroOps = 5;
+}
+
+def JWriteCMPXCHGVariant :  SchedWriteVariant<[
+  SchedVar<MCSchedPredicate<IsAtomicCompareAndSwap_8>, [JWriteLOCK_CMPXCHG8rm]>,
+  SchedVar<MCSchedPredicate<IsAtomicCompareAndSwap>,   [JWriteLOCK_CMPXCHGrm]>,
+  SchedVar<MCSchedPredicate<IsRegMemCompareAndSwap_8>, [JWriteCMPXCHG8rm]>,
+  SchedVar<MCSchedPredicate<IsRegMemCompareAndSwap>,   [WriteCMPXCHGRMW]>,
+  SchedVar<MCSchedPredicate<IsRegRegCompareAndSwap_8>, [JWriteCMPXCHG8rr]>,
+  SchedVar<NoSchedPred,                                [WriteCMPXCHG]>
+]>;
+def : InstRW<[JWriteCMPXCHGVariant], (instrs CMPXCHG8rr, LCMPXCHG8, CMPXCHG8rm,
+                                             CMPXCHG16rm, CMPXCHG32rm, CMPXCHG64rm,
+                                             LCMPXCHG16, LCMPXCHG32, LCMPXCHG64,
+                                             CMPXCHG8B, CMPXCHG16B,
+                                             LCMPXCHG8B, LCMPXCHG16B)>;
+
+
 ////////////////////////////////////////////////////////////////////////////////
 // Floating point. This covers both scalar and vector operations.
 ////////////////////////////////////////////////////////////////////////////////
 
 defm : X86WriteRes<WriteFLD0,          [JFPU1, JSTC], 3, [1,1], 1>;
 defm : X86WriteRes<WriteFLD1,          [JFPU1, JSTC], 3, [1,1], 1>;
 defm : X86WriteRes<WriteFLDC,          [JFPU1, JSTC], 3, [1,1], 1>;
 defm : X86WriteRes<WriteFLoad,         [JLAGU, JFPU01, JFPX], 5, [1, 1, 1], 1>;

test/tools/llvm-mca/X86/BtVer2/resources-cmpxchg.s

 # NOTE: Assertions have been autogenerated by utils/update_mca_test_checks.py
 # RUN: llvm-mca -mtriple=x86_64-unknown-unknown -mcpu=btver2 -instruction-tables < %s | FileCheck %s
 
 cmpxchg8b  (%rax)
 cmpxchg16b (%rax)
 lock cmpxchg8b  (%rax)
 lock cmpxchg16b (%rax)
 
 cmpxchgb  %bl, %cl
 cmpxchgw  %bx, %cx
 cmpxchgl  %ebx, %ecx
 cmpxchgq  %rbx, %rcx
 
 cmpxchgb  %bl, (%rsi)
 cmpxchgw  %bx, (%rsi)
 cmpxchgl  %ebx, (%rsi)
 cmpxchgq  %rbx, (%rsi)
 
 lock cmpxchgb  %bl, (%rsi)
 lock cmpxchgw  %bx, (%rsi)
 lock cmpxchgl  %ebx, (%rsi)
 lock cmpxchgq  %rbx, (%rsi)
 
 # CHECK:      Instruction Info:
 # CHECK-NEXT: [1]: #uOps
 # CHECK-NEXT: [2]: Latency
 # CHECK-NEXT: [3]: RThroughput
 # CHECK-NEXT: [4]: MayLoad
 # CHECK-NEXT: [5]: MayStore
 # CHECK-NEXT: [6]: HasSideEffects (U)
 
 # CHECK:      [1]    [2]    [3]    [4]    [5]    [6]    Instructions:
-# CHECK-NEXT:  2      4     1.00    *      *            cmpxchg8b (%rax)
-# CHECK-NEXT:  2      4     1.00    *      *            cmpxchg16b  (%rax)
-# CHECK-NEXT:  2      4     1.00    *      *            lock    cmpxchg8b (%rax)
-# CHECK-NEXT:  2      4     1.00    *      *            lock    cmpxchg16b  (%rax)
-# CHECK-NEXT:  1      1     0.50                        cmpxchgb  %bl, %cl
-# CHECK-NEXT:  1      1     0.50                        cmpxchgw  %bx, %cx
-# CHECK-NEXT:  1      1     0.50                        cmpxchgl  %ebx, %ecx
-# CHECK-NEXT:  1      1     0.50                        cmpxchgq  %rbx, %rcx
-# CHECK-NEXT:  2      4     1.00    *      *            cmpxchgb  %bl, (%rsi)
-# CHECK-NEXT:  2      4     1.00    *      *            cmpxchgw  %bx, (%rsi)
-# CHECK-NEXT:  2      4     1.00    *      *            cmpxchgl  %ebx, (%rsi)
-# CHECK-NEXT:  2      4     1.00    *      *            cmpxchgq  %rbx, (%rsi)
-# CHECK-NEXT:  2      4     1.00    *      *            lock    cmpxchgb  %bl, (%rsi)
-# CHECK-NEXT:  2      4     1.00    *      *            lock    cmpxchgw  %bx, (%rsi)
-# CHECK-NEXT:  2      4     1.00    *      *            lock    cmpxchgl  %ebx, (%rsi)
-# CHECK-NEXT:  2      4     1.00    *      *            lock    cmpxchgq  %rbx, (%rsi)
+# CHECK-NEXT:  6      11    1.50    *      *            cmpxchg8b (%rax)
+# CHECK-NEXT:  6      11    1.50    *      *            cmpxchg16b  (%rax)
+# CHECK-NEXT:  6      17    17.00   *      *            lock    cmpxchg8b (%rax)
+# CHECK-NEXT:  6      17    17.00   *      *            lock    cmpxchg16b  (%rax)
+# CHECK-NEXT:  3      3     1.50                        cmpxchgb  %bl, %cl
+# CHECK-NEXT:  5      3     1.50                        cmpxchgw  %bx, %cx
+# CHECK-NEXT:  5      3     1.50                        cmpxchgl  %ebx, %ecx
+# CHECK-NEXT:  5      3     1.50                        cmpxchgq  %rbx, %rcx
+# CHECK-NEXT:  5      11    1.50    *      *            cmpxchgb  %bl, (%rsi)
+# CHECK-NEXT:  6      11    1.50    *      *            cmpxchgw  %bx, (%rsi)
+# CHECK-NEXT:  6      11    1.50    *      *            cmpxchgl  %ebx, (%rsi)
+# CHECK-NEXT:  6      11    1.50    *      *            cmpxchgq  %rbx, (%rsi)
+# CHECK-NEXT:  5      16    16.00   *      *            lock    cmpxchgb  %bl, (%rsi)
+# CHECK-NEXT:  6      17    17.00   *      *            lock    cmpxchgw  %bx, (%rsi)
+# CHECK-NEXT:  6      17    17.00   *      *            lock    cmpxchgl  %ebx, (%rsi)
+# CHECK-NEXT:  6      17    17.00   *      *            lock    cmpxchgq  %rbx, (%rsi)
 
 # CHECK:      Resources:
 # CHECK-NEXT: [0]   - JALU0
 # CHECK-NEXT: [1]   - JALU1
 # CHECK-NEXT: [2]   - JDiv
 # CHECK-NEXT: [3]   - JFPA
 # CHECK-NEXT: [4]   - JFPM
 # CHECK-NEXT: [5]   - JFPU0
 # CHECK-NEXT: [6]   - JFPU1
 # CHECK-NEXT: [7]   - JLAGU
 # CHECK-NEXT: [8]   - JMul
 # CHECK-NEXT: [9]   - JSAGU
 # CHECK-NEXT: [10]  - JSTC
 # CHECK-NEXT: [11]  - JVALU0
 # CHECK-NEXT: [12]  - JVALU1
 # CHECK-NEXT: [13]  - JVIMUL
 
 # CHECK:      Resource pressure per iteration:
 # CHECK-NEXT: [0]    [1]    [2]    [3]    [4]    [5]    [6]    [7]    [8]    [9]    [10]   [11]   [12]   [13]
-# CHECK-NEXT: 8.00   8.00    -      -      -      -      -     12.00   -     12.00   -      -      -      -
+# CHECK-NEXT: 24.00  24.00   -      -      -      -      -     107.00  -     107.00  -      -      -      -
 
 # CHECK:      Resource pressure by instruction:
 # CHECK-NEXT: [0]    [1]    [2]    [3]    [4]    [5]    [6]    [7]    [8]    [9]    [10]   [11]   [12]   [13]   Instructions:
-# CHECK-NEXT: 0.50   0.50    -      -      -      -      -     1.00    -     1.00    -      -      -      -     cmpxchg8b (%rax)
-# CHECK-NEXT: 0.50   0.50    -      -      -      -      -     1.00    -     1.00    -      -      -      -     cmpxchg16b  (%rax)
-# CHECK-NEXT: 0.50   0.50    -      -      -      -      -     1.00    -     1.00    -      -      -      -     lock    cmpxchg8b  (%rax)
-# CHECK-NEXT: 0.50   0.50    -      -      -      -      -     1.00    -     1.00    -      -      -      -     lock    cmpxchg16b  (%rax)
-# CHECK-NEXT: 0.50   0.50    -      -      -      -      -      -      -      -      -      -      -      -     cmpxchgb  %bl, %cl
-# CHECK-NEXT: 0.50   0.50    -      -      -      -      -      -      -      -      -      -      -      -     cmpxchgw  %bx, %cx
-# CHECK-NEXT: 0.50   0.50    -      -      -      -      -      -      -      -      -      -      -      -     cmpxchgl  %ebx, %ecx
-# CHECK-NEXT: 0.50   0.50    -      -      -      -      -      -      -      -      -      -      -      -     cmpxchgq  %rbx, %rcx
-# CHECK-NEXT: 0.50   0.50    -      -      -      -      -     1.00    -     1.00    -      -      -      -     cmpxchgb  %bl, (%rsi)
-# CHECK-NEXT: 0.50   0.50    -      -      -      -      -     1.00    -     1.00    -      -      -      -     cmpxchgw  %bx, (%rsi)
-# CHECK-NEXT: 0.50   0.50    -      -      -      -      -     1.00    -     1.00    -      -      -      -     cmpxchgl  %ebx, (%rsi)
-# CHECK-NEXT: 0.50   0.50    -      -      -      -      -     1.00    -     1.00    -      -      -      -     cmpxchgq  %rbx, (%rsi)
-# CHECK-NEXT: 0.50   0.50    -      -      -      -      -     1.00    -     1.00    -      -      -      -     lock    cmpxchgb  %bl, (%rsi)
-# CHECK-NEXT: 0.50   0.50    -      -      -      -      -     1.00    -     1.00    -      -      -      -     lock    cmpxchgw  %bx, (%rsi)
-# CHECK-NEXT: 0.50   0.50    -      -      -      -      -     1.00    -     1.00    -      -      -      -     lock    cmpxchgl  %ebx, (%rsi)
-# CHECK-NEXT: 0.50   0.50    -      -      -      -      -     1.00    -     1.00    -      -      -      -     lock    cmpxchgq  %rbx, (%rsi)
+# CHECK-NEXT: 1.50   1.50    -      -      -      -      -     1.00    -     1.00    -      -      -      -     cmpxchg8b (%rax)
+# CHECK-NEXT: 1.50   1.50    -      -      -      -      -     1.00    -     1.00    -      -      -      -     cmpxchg16b  (%rax)
+# CHECK-NEXT: 1.50   1.50    -      -      -      -      -     17.00   -     17.00   -      -      -      -     lock    cmpxchg8b  (%rax)
+# CHECK-NEXT: 1.50   1.50    -      -      -      -      -     17.00   -     17.00   -      -      -      -     lock    cmpxchg16b  (%rax)
+# CHECK-NEXT: 1.50   1.50    -      -      -      -      -      -      -      -      -      -      -      -     cmpxchgb  %bl, %cl
+# CHECK-NEXT: 1.50   1.50    -      -      -      -      -      -      -      -      -      -      -      -     cmpxchgw  %bx, %cx
+# CHECK-NEXT: 1.50   1.50    -      -      -      -      -      -      -      -      -      -      -      -     cmpxchgl  %ebx, %ecx
+# CHECK-NEXT: 1.50   1.50    -      -      -      -      -      -      -      -      -      -      -      -     cmpxchgq  %rbx, %rcx
+# CHECK-NEXT: 1.50   1.50    -      -      -      -      -     1.00    -     1.00    -      -      -      -     cmpxchgb  %bl, (%rsi)
+# CHECK-NEXT: 1.50   1.50    -      -      -      -      -     1.00    -     1.00    -      -      -      -     cmpxchgw  %bx, (%rsi)
+# CHECK-NEXT: 1.50   1.50    -      -      -      -      -     1.00    -     1.00    -      -      -      -     cmpxchgl  %ebx, (%rsi)
+# CHECK-NEXT: 1.50   1.50    -      -      -      -      -     1.00    -     1.00    -      -      -      -     cmpxchgq  %rbx, (%rsi)
+# CHECK-NEXT: 1.50   1.50    -      -      -      -      -     16.00   -     16.00   -      -      -      -     lock    cmpxchgb  %bl, (%rsi)
+# CHECK-NEXT: 1.50   1.50    -      -      -      -      -     17.00   -     17.00   -      -      -      -     lock    cmpxchgw  %bx, (%rsi)
+# CHECK-NEXT: 1.50   1.50    -      -      -      -      -     17.00   -     17.00   -      -      -      -     lock    cmpxchgl  %ebx, (%rsi)
+# CHECK-NEXT: 1.50   1.50    -      -      -      -      -     17.00   -     17.00   -      -      -      -     lock    cmpxchgq  %rbx, (%rsi)

test/tools/llvm-mca/X86/BtVer2/resources-x86_64.s

 # CHECK-NEXT:  1      4     1.00    *                   cmpq  $7, (%rax)
 # CHECK-NEXT:  1      1     0.50                        cmpq  %rsi, %rdi
 # CHECK-NEXT:  1      4     1.00    *                   cmpq  %rsi, (%rax)
 # CHECK-NEXT:  1      4     1.00    *                   cmpq  (%rax), %rdi
 # CHECK-NEXT:  1      100   0.50                  U     cmpsb %es:(%rdi), (%rsi)
 # CHECK-NEXT:  1      100   0.50                  U     cmpsw %es:(%rdi), (%rsi)
 # CHECK-NEXT:  1      100   0.50                  U     cmpsl %es:(%rdi), (%rsi)
 # CHECK-NEXT:  1      100   0.50                  U     cmpsq %es:(%rdi), (%rsi)
-# CHECK-NEXT:  1      1     0.50                        cmpxchgb  %cl, %bl
-# CHECK-NEXT:  2      4     1.00    *      *            cmpxchgb  %cl, (%rbx)
-# CHECK-NEXT:  1      1     0.50                        cmpxchgw  %cx, %bx
-# CHECK-NEXT:  2      4     1.00    *      *            cmpxchgw  %cx, (%rbx)
-# CHECK-NEXT:  1      1     0.50                        cmpxchgl  %ecx, %ebx
-# CHECK-NEXT:  2      4     1.00    *      *            cmpxchgl  %ecx, (%rbx)
-# CHECK-NEXT:  1      1     0.50                        cmpxchgq  %rcx, %rbx
-# CHECK-NEXT:  2      4     1.00    *      *            cmpxchgq  %rcx, (%rbx)
+# CHECK-NEXT:  3      3     1.50                        cmpxchgb  %cl, %bl
+# CHECK-NEXT:  5      11    1.50    *      *            cmpxchgb  %cl, (%rbx)
+# CHECK-NEXT:  5      3     1.50                        cmpxchgw  %cx, %bx
+# CHECK-NEXT:  6      11    1.50    *      *            cmpxchgw  %cx, (%rbx)
+# CHECK-NEXT:  5      3     1.50                        cmpxchgl  %ecx, %ebx
+# CHECK-NEXT:  6      11    1.50    *      *            cmpxchgl  %ecx, (%rbx)
+# CHECK-NEXT:  5      3     1.50                        cmpxchgq  %rcx, %rbx
+# CHECK-NEXT:  6      11    1.50    *      *            cmpxchgq  %rcx, (%rbx)
 # CHECK-NEXT:  1      100   0.50                  U     cpuid
 # CHECK-NEXT:  1      1     0.50                        decb  %dil
 # CHECK-NEXT:  1      5     1.00    *      *            decb  (%rax)
 # CHECK-NEXT:  1      1     0.50                        decw  %di
 # CHECK-NEXT:  1      5     1.00    *      *            decw  (%rax)
 # CHECK-NEXT:  1      1     0.50                        decl  %edi
 # CHECK-NEXT:  1      5     1.00    *      *            decl  (%rax)
 # CHECK-NEXT:  1      1     0.50                        decq  %rdi

 # CHECK-NEXT: [9]   - JSAGU
 # CHECK-NEXT: [10]  - JSTC
 # CHECK-NEXT: [11]  - JVALU0
 # CHECK-NEXT: [12]  - JVALU1
 # CHECK-NEXT: [13]  - JVIMUL
 
 # CHECK:      Resource pressure per iteration:
 # CHECK-NEXT: [0]    [1]    [2]    [3]    [4]    [5]    [6]    [7]    [8]    [9]    [10]   [11]   [12]   [13]
-# CHECK-NEXT: 610.00 660.00 380.00  -      -      -      -     330.00 64.00  231.00  -      -      -      -
+# CHECK-NEXT: 618.00 668.00 380.00  -      -      -      -     330.00 64.00  231.00  -      -      -      -
 
 # CHECK:      Resource pressure by instruction:
 # CHECK-NEXT: [0]    [1]    [2]    [3]    [4]    [5]    [6]    [7]    [8]    [9]    [10]   [11]   [12]   [13]   Instructions:
 # CHECK-NEXT: 1.00   1.00    -      -      -      -      -      -      -      -      -      -      -      -     adcb  $0, %al
 # CHECK-NEXT: 1.00   1.00    -      -      -      -      -      -      -      -      -      -      -      -     adcb  $0, %dil
 # CHECK-NEXT: 1.00   1.00    -      -      -      -      -     1.00    -     1.00    -      -      -      -     adcb  $0, (%rax)
 # CHECK-NEXT: 1.00   1.00    -      -      -      -      -      -      -      -      -      -      -      -     adcb  $7, %al
 # CHECK-NEXT: 1.00   1.00    -      -      -      -      -      -      -      -      -      -      -      -     adcb  $7, %dil

 # CHECK-NEXT: 0.50   0.50    -      -      -      -      -     1.00    -      -      -      -      -      -     cmpq  $7, (%rax)
 # CHECK-NEXT: 0.50   0.50    -      -      -      -      -      -      -      -      -      -      -      -     cmpq  %rsi, %rdi
 # CHECK-NEXT: 0.50   0.50    -      -      -      -      -     1.00    -      -      -      -      -      -     cmpq  %rsi, (%rax)
 # CHECK-NEXT: 0.50   0.50    -      -      -      -      -     1.00    -      -      -      -      -      -     cmpq  (%rax), %rdi
 # CHECK-NEXT: 0.50   0.50    -      -      -      -      -      -      -      -      -      -      -      -     cmpsb %es:(%rdi), (%rsi)
 # CHECK-NEXT: 0.50   0.50    -      -      -      -      -      -      -      -      -      -      -      -     cmpsw %es:(%rdi), (%rsi)
 # CHECK-NEXT: 0.50   0.50    -      -      -      -      -      -      -      -      -      -      -      -     cmpsl %es:(%rdi), (%rsi)
 # CHECK-NEXT: 0.50   0.50    -      -      -      -      -      -      -      -      -      -      -      -     cmpsq %es:(%rdi), (%rsi)
-# CHECK-NEXT: 0.50   0.50    -      -      -      -      -      -      -      -      -      -      -      -     cmpxchgb  %cl, %bl
-# CHECK-NEXT: 0.50   0.50    -      -      -      -      -     1.00    -     1.00    -      -      -      -     cmpxchgb  %cl, (%rbx)
-# CHECK-NEXT: 0.50   0.50    -      -      -      -      -      -      -      -      -      -      -      -     cmpxchgw  %cx, %bx
-# CHECK-NEXT: 0.50   0.50    -      -      -      -      -     1.00    -     1.00    -      -      -      -     cmpxchgw  %cx, (%rbx)
-# CHECK-NEXT: 0.50   0.50    -      -      -      -      -      -      -      -      -      -      -      -     cmpxchgl  %ecx, %ebx
-# CHECK-NEXT: 0.50   0.50    -      -      -      -      -     1.00    -     1.00    -      -      -      -     cmpxchgl  %ecx, (%rbx)
-# CHECK-NEXT: 0.50   0.50    -      -      -      -      -      -      -      -      -      -      -      -     cmpxchgq  %rcx, %rbx
-# CHECK-NEXT: 0.50   0.50    -      -      -      -      -     1.00    -     1.00    -      -      -      -     cmpxchgq  %rcx, (%rbx)
+# CHECK-NEXT: 1.50   1.50    -      -      -      -      -      -      -      -      -      -      -      -     cmpxchgb  %cl, %bl
+# CHECK-NEXT: 1.50   1.50    -      -      -      -      -     1.00    -     1.00    -      -      -      -     cmpxchgb  %cl, (%rbx)
+# CHECK-NEXT: 1.50   1.50    -      -      -      -      -      -      -      -      -      -      -      -     cmpxchgw  %cx, %bx
+# CHECK-NEXT: 1.50   1.50    -      -      -      -      -     1.00    -     1.00    -      -      -      -     cmpxchgw  %cx, (%rbx)
+# CHECK-NEXT: 1.50   1.50    -      -      -      -      -      -      -      -      -      -      -      -     cmpxchgl  %ecx, %ebx
+# CHECK-NEXT: 1.50   1.50    -      -      -      -      -     1.00    -     1.00    -      -      -      -     cmpxchgl  %ecx, (%rbx)
+# CHECK-NEXT: 1.50   1.50    -      -      -      -      -      -      -      -      -      -      -      -     cmpxchgq  %rcx, %rbx
+# CHECK-NEXT: 1.50   1.50    -      -      -      -      -     1.00    -     1.00    -      -      -      -     cmpxchgq  %rcx, (%rbx)
 # CHECK-NEXT: 0.50   0.50    -      -      -      -      -      -      -      -      -      -      -      -     cpuid
 # CHECK-NEXT: 0.50   0.50    -      -      -      -      -      -      -      -      -      -      -      -     decb  %dil
 # CHECK-NEXT: 0.50   0.50    -      -      -      -      -     1.00    -     1.00    -      -      -      -     decb  (%rax)
 # CHECK-NEXT: 0.50   0.50    -      -      -      -      -      -      -      -      -      -      -      -     decw  %di
 # CHECK-NEXT: 0.50   0.50    -      -      -      -      -     1.00    -     1.00    -      -      -      -     decw  (%rax)
 # CHECK-NEXT: 0.50   0.50    -      -      -      -      -      -      -      -      -      -      -      -     decl  %edi
 # CHECK-NEXT: 0.50   0.50    -      -      -      -      -     1.00    -     1.00    -      -      -      -     decl  (%rax)
 # CHECK-NEXT: 0.50   0.50    -      -      -      -      -      -      -      -      -      -      -      -     decq  %rdi