[AArch64] Initial Ampere1B scheduling model

[ptomsich]

The Ampere1B core is enabled with a new scheduling/pipeline model, as it provides significant updates over the Ampere1 core; it reduces latencies on many instructions, has some micro-ops reassigned between the XY and X units, and provides modelling for the instructions added since Ampere1 and Ampere1A.

As this is the first model implementing the CSSC instructions, we update the UnsupportedFeatures on all other models (that have CompleteModel set).

Testcases are added under llvm-mca: these showed the FullFP16 feature missing, so we are adding it in as part of this commit.

This adds tests and additional fixes compared to the reverted #81338.

[llvmbot]

@llvm/pr-subscribers-backend-aarch64

Author: Philipp Tomsich (ptomsich)

Changes

The Ampere1B core is enabled with a new scheduling/pipeline model, as it provides significant updates over the Ampere1 core; it reduces latencies on many instructions, has some micro-ops reassigned between the XY and X units, and provides modelling for the instructions added since Ampere1 and Ampere1A.

This is identical to the reverted #81338, but has the missing ',' added and was retested after a 'ninja clean'.

---

Patch is 44.09 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/81341.diff

2 Files Affected:

• (modified) llvm/lib/Target/AArch64/AArch64.td (+2-1)
• (added) llvm/lib/Target/AArch64/AArch64SchedAmpere1B.td (+1063)

diff --git a/llvm/lib/Target/AArch64/AArch64.td b/llvm/lib/Target/AArch64/AArch64.td
index e76204f5522515..156c48e02abf9c 100644
--- a/llvm/lib/Target/AArch64/AArch64.td
+++ b/llvm/lib/Target/AArch64/AArch64.td
@@ -837,6 +837,7 @@ include "AArch64SchedA64FX.td"
 include "AArch64SchedThunderX3T110.td"
 include "AArch64SchedTSV110.td"
 include "AArch64SchedAmpere1.td"
+include "AArch64SchedAmpere1B.td"
 include "AArch64SchedNeoverseN1.td"
 include "AArch64SchedNeoverseN2.td"
 include "AArch64SchedNeoverseV1.td"
@@ -1722,7 +1723,7 @@ def : ProcessorModel<"ampere1", Ampere1Model, ProcessorFeatures.Ampere1,
 def : ProcessorModel<"ampere1a", Ampere1Model, ProcessorFeatures.Ampere1A,
                      [TuneAmpere1A]>;
 
-def : ProcessorModel<"ampere1b", Ampere1Model, ProcessorFeatures.Ampere1B,
+def : ProcessorModel<"ampere1b", Ampere1BModel, ProcessorFeatures.Ampere1B,
                      [TuneAmpere1B]>;
 
 //===----------------------------------------------------------------------===//
diff --git a/llvm/lib/Target/AArch64/AArch64SchedAmpere1B.td b/llvm/lib/Target/AArch64/AArch64SchedAmpere1B.td
new file mode 100644
index 00000000000000..28c93c2b06aa11
--- /dev/null
+++ b/llvm/lib/Target/AArch64/AArch64SchedAmpere1B.td
@@ -0,0 +1,1063 @@
+//=- AArch64SchedAmpere1B.td - Ampere-1B scheduling def -----*- tablegen -*-=//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines the machine model for the Ampere Computing Ampere-1B to
+// support instruction scheduling and other instruction cost heuristics.
+//
+//===----------------------------------------------------------------------===//
+
+// The Ampere-1 core is an out-of-order micro-architecture.  The front
+// end has branch prediction, with a 10-cycle recovery time from a
+// mispredicted branch.  Instructions coming out of the front end are
+// decoded into internal micro-ops (uops).
+
+def Ampere1BModel : SchedMachineModel {
+  let IssueWidth            =   4;  // 4-way decode and dispatch
+  let MicroOpBufferSize     = 192;  // micro-op re-order buffer size
+  let LoadLatency           =   3;  // Optimistic load latency
+  let MispredictPenalty     =  10;  // Branch mispredict penalty
+  let LoopMicroOpBufferSize =  32;  // Instruction queue size
+  let CompleteModel = 0;
+
+  list<Predicate> UnsupportedFeatures = !listconcat(SVEUnsupported.F,
+                                                    SMEUnsupported.F,
+                                                    PAUnsupported.F);
+}
+
+let SchedModel = Ampere1BModel in {
+
+//===----------------------------------------------------------------------===//
+// Define each kind of processor resource and number available on Ampere-1.
+// Ampere-1 has 12 pipelines that 8 independent scheduler (4 integer, 2 FP,
+// and 2 memory) issue into.  The integer and FP schedulers can each issue
+// one uop per cycle, while the memory schedulers can each issue one load
+// and one store address calculation per cycle.
+
+def Ampere1BUnitA  : ProcResource<2>;  // integer single-cycle, branch, and flags r/w
+def Ampere1BUnitB  : ProcResource<2>;  // integer single-cycle, and complex shifts
+def Ampere1BUnitBS : ProcResource<1>;  // integer multi-cycle
+def Ampere1BUnitL  : ProcResource<2>;  // load
+def Ampere1BUnitS  : ProcResource<2>;  // store address calculation
+def Ampere1BUnitX  : ProcResource<1>;  // FP and vector operations, and flag write
+def Ampere1BUnitY  : ProcResource<1>;  // FP and vector operations, and crypto
+def Ampere1BUnitZ  : ProcResource<1>;  // FP store data and FP-to-integer moves
+
+def Ampere1BUnitAB : ProcResGroup<[Ampere1BUnitA, Ampere1BUnitB]>;
+def Ampere1BUnitXY : ProcResGroup<[Ampere1BUnitX, Ampere1BUnitY]>;
+
+//===----------------------------------------------------------------------===//
+// Define customized scheduler read/write types specific to the Ampere-1.
+
+def Ampere1BWrite_1cyc_1A : SchedWriteRes<[Ampere1BUnitA]> {
+  let Latency = 1;
+  let NumMicroOps = 1;
+}
+
+def Ampere1BWrite_1cyc_2A : SchedWriteRes<[Ampere1BUnitA, Ampere1BUnitA]> {
+  let Latency = 1;
+  let NumMicroOps = 2;
+}
+
+def Ampere1BWrite_1cyc_1B : SchedWriteRes<[Ampere1BUnitB]> {
+  let Latency = 1;
+  let NumMicroOps = 1;
+}
+
+def Ampere1BWrite_1cyc_1BS : SchedWriteRes<[Ampere1BUnitBS]> {
+  let Latency = 1;
+  let NumMicroOps = 1;
+}
+
+def Ampere1BWrite_1cyc_1BS_1B : SchedWriteRes<[Ampere1BUnitBS, Ampere1BUnitB]> {
+  let Latency = 1;
+  let NumMicroOps = 2;
+}
+
+def Ampere1BWrite_1cyc_1AB : SchedWriteRes<[Ampere1BUnitAB]> {
+  let Latency = 1;
+  let NumMicroOps = 1;
+}
+
+def Ampere1BWrite_1cyc_1AB_1A : SchedWriteRes<[Ampere1BUnitAB, Ampere1BUnitA]> {
+  let Latency = 1;
+  let NumMicroOps = 2;
+}
+
+def Ampere1BWrite_1cyc_1L : SchedWriteRes<[Ampere1BUnitL]> {
+  let Latency = 1;
+  let NumMicroOps = 1;
+}
+
+def Ampere1BWrite_1cyc_1S : SchedWriteRes<[Ampere1BUnitS]> {
+  let Latency = 1;
+  let NumMicroOps = 1;
+}
+
+def Ampere1BWrite_1cyc_2S : SchedWriteRes<[Ampere1BUnitS, Ampere1BUnitS]> {
+  let Latency = 1;
+  let NumMicroOps = 2;
+}
+
+def Ampere1BWrite_2cyc_1Y : SchedWriteRes<[Ampere1BUnitY]> {
+  let Latency = 2;
+  let NumMicroOps = 1;
+}
+
+def Ampere1BWrite_2cyc_2AB : SchedWriteRes<[Ampere1BUnitAB, Ampere1BUnitAB]> {
+  let Latency = 2;
+  let NumMicroOps = 2;
+}
+
+def Ampere1BWrite_2cyc_1B_1AB : SchedWriteRes<[Ampere1BUnitB, Ampere1BUnitAB]> {
+  let Latency = 2;
+  let NumMicroOps = 2;
+}
+
+def Ampere1BWrite_2cyc_1B_1S : SchedWriteRes<[Ampere1BUnitB, Ampere1BUnitS]> {
+  let Latency = 2;
+  let NumMicroOps = 2;
+}
+
+def Ampere1BWrite_2cyc_1B_1S_1AB : SchedWriteRes<[Ampere1BUnitB,
+                                                  Ampere1BUnitS,
+                                                  Ampere1BUnitAB]> {
+  let Latency = 2;
+  let NumMicroOps = 3;
+}
+
+def Ampere1BWrite_2cyc_1XY : SchedWriteRes<[Ampere1BUnitXY]> {
+  let Latency = 2;
+  let NumMicroOps = 1;
+}
+
+def Ampere1BWrite_2cyc_1S_1Z : SchedWriteRes<[Ampere1BUnitS, Ampere1BUnitZ]> {
+  let Latency = 2;
+  let NumMicroOps = 2;
+}
+
+def Ampere1BWrite_3cyc_1BS : SchedWriteRes<[Ampere1BUnitBS]> {
+  let Latency = 3;
+  let NumMicroOps = 1;
+}
+
+def Ampere1BWrite_3cyc_1L : SchedWriteRes<[Ampere1BUnitL]> {
+  let Latency = 3;
+  let NumMicroOps = 1;
+}
+
+def Ampere1BWrite_3cyc_1X : SchedWriteRes<[Ampere1BUnitX]> {
+  let Latency = 3;
+  let NumMicroOps = 1;
+}
+
+def Ampere1BWrite_3cyc_1XY : SchedWriteRes<[Ampere1BUnitXY]> {
+  let Latency = 3;
+  let NumMicroOps = 1;
+}
+
+def Ampere1BWrite_3cyc_1Z : SchedWriteRes<[Ampere1BUnitZ]> {
+  let Latency = 3;
+  let NumMicroOps = 1;
+}
+
+def Ampere1BWrite_3cyc_1S_1Z : SchedWriteRes<[Ampere1BUnitS,
+                                              Ampere1BUnitZ]> {
+  let Latency = 3;
+  let NumMicroOps = 2;
+}
+
+def Ampere1BWrite_3cyc_1S_2Z : SchedWriteRes<[Ampere1BUnitS,
+                                              Ampere1BUnitZ, Ampere1BUnitZ]> {
+  let Latency = 3;
+  let NumMicroOps = 3;
+}
+
+def Ampere1BWrite_3cyc_2S_2Z : SchedWriteRes<[Ampere1BUnitS, Ampere1BUnitS,
+                                              Ampere1BUnitZ, Ampere1BUnitZ]> {
+  let Latency = 3;
+  let NumMicroOps = 4;
+}
+
+def Ampere1BWrite_4cyc_1BS_1AB : SchedWriteRes<[Ampere1BUnitBS, Ampere1BUnitAB]> {
+  let Latency = 4;
+  let NumMicroOps = 2;
+}
+
+def Ampere1BWrite_4cyc_1L : SchedWriteRes<[Ampere1BUnitL]> {
+  let Latency = 4;
+  let NumMicroOps = 1;
+}
+
+def Ampere1BWrite_4cyc_1L_1B : SchedWriteRes<[Ampere1BUnitL, Ampere1BUnitB]> {
+  let Latency = 4;
+  let NumMicroOps = 2;
+}
+
+def Ampere1BWrite_4cyc_1X : SchedWriteRes<[Ampere1BUnitX]> {
+  let Latency = 4;
+  let NumMicroOps = 1;
+}
+
+def Ampere1BWrite_4cyc_1XY : SchedWriteRes<[Ampere1BUnitXY]> {
+  let Latency = 4;
+  let NumMicroOps = 1;
+}
+
+def Ampere1BWrite_4cyc_2XY : SchedWriteRes<[Ampere1BUnitXY, Ampere1BUnitXY]> {
+  let Latency = 4;
+  let NumMicroOps = 2;
+}
+
+def Ampere1BWrite_5cyc_1BS : SchedWriteRes<[Ampere1BUnitBS]> {
+  let Latency = 5;
+  let NumMicroOps = 1;
+}
+
+def Ampere1BWrite_4cyc_1XY_1S_1Z : SchedWriteRes<[Ampere1BUnitXY,
+                                                  Ampere1BUnitS,
+                                                  Ampere1BUnitZ]> {
+  let Latency = 4;
+  let NumMicroOps = 3;
+}
+
+def Ampere1BWrite_5cyc_1BS : SchedWriteRes<[Ampere1BUnitBS]> {
+  let Latency = 5;
+  let NumMicroOps = 1;
+}
+
+def Ampere1BWrite_5cyc_4S_4Z : SchedWriteRes<[Ampere1BUnitS, Ampere1BUnitS,
+                                              Ampere1BUnitS, Ampere1BUnitS,
+                                              Ampere1BUnitZ, Ampere1BUnitZ,
+                                              Ampere1BUnitZ, Ampere1BUnitZ]> {
+  let Latency = 5;
+  let NumMicroOps = 8;
+}
+
+def Ampere1BWrite_5cyc_1L_1BS : SchedWriteRes<[Ampere1BUnitL,
+                                               Ampere1BUnitBS]> {
+  let Latency = 5;
+  let NumMicroOps = 2;
+}
+
+def Ampere1BWrite_5cyc_3L : SchedWriteRes<[Ampere1BUnitL,
+                                           Ampere1BUnitL,
+                                           Ampere1BUnitL]> {
+  let Latency = 5;
+  let NumMicroOps = 3;
+}
+
+def Ampere1BWrite_5cyc_4L : SchedWriteRes<[Ampere1BUnitL,
+                                           Ampere1BUnitL,
+                                           Ampere1BUnitL,
+                                           Ampere1BUnitL]> {
+  let Latency = 5;
+  let NumMicroOps = 4;
+}
+
+def Ampere1BWrite_5cyc_1X : SchedWriteRes<[Ampere1BUnitX]> {
+  let Latency = 5;
+  let NumMicroOps = 1;
+}
+
+def Ampere1BWrite_5cyc_2XY_2S_2Z : SchedWriteRes<[Ampere1BUnitXY, Ampere1BUnitXY,
+                                                  Ampere1BUnitS,  Ampere1BUnitS,
+                                                  Ampere1BUnitZ,  Ampere1BUnitZ]> {
+  let Latency = 5;
+  let NumMicroOps = 6;
+}
+
+def Ampere1BWrite_6cyc_1BS_1A : SchedWriteRes<[Ampere1BUnitBS, Ampere1BUnitA]> {
+  let Latency = 6;
+  let NumMicroOps = 2;
+}
+
+def Ampere1BWrite_6cyc_1BS_2A : SchedWriteRes<[Ampere1BUnitBS, Ampere1BUnitA,
+                                                               Ampere1BUnitA]> {
+  let Latency = 6;
+  let NumMicroOps = 3;
+}
+
+def Ampere1BWrite_6cyc_1X : SchedWriteRes<[Ampere1BUnitX]> {
+  let Latency = 6;
+  let NumMicroOps = 2;
+}
+
+def Ampere1BWrite_6cyc_2XY : SchedWriteRes<[Ampere1BUnitXY, Ampere1BUnitXY]> {
+  let Latency = 6;
+  let NumMicroOps = 2;
+}
+
+def Ampere1BWrite_6cyc_3XY : SchedWriteRes<[Ampere1BUnitXY, Ampere1BUnitXY,
+                                            Ampere1BUnitXY]> {
+  let Latency = 6;
+  let NumMicroOps = 3;
+}
+
+def Ampere1BWrite_6cyc_2XY_2S_2Z : SchedWriteRes<[Ampere1BUnitXY, Ampere1BUnitXY,
+                                                  Ampere1BUnitS,  Ampere1BUnitS,
+                                                  Ampere1BUnitZ,  Ampere1BUnitZ]> {
+  let Latency = 6;
+  let NumMicroOps = 6;
+}
+
+def Ampere1BWrite_6cyc_3XY_3S_3Z : SchedWriteRes<[Ampere1BUnitXY, Ampere1BUnitXY, Ampere1BUnitXY,
+                                                  Ampere1BUnitS,  Ampere1BUnitS,  Ampere1BUnitS,
+                                                  Ampere1BUnitZ,  Ampere1BUnitZ,  Ampere1BUnitZ]> {
+  let Latency = 6;
+  let NumMicroOps = 9;
+}
+
+def Ampere1BWrite_7cyc_1BS_1XY : SchedWriteRes<[Ampere1BUnitBS, Ampere1BUnitXY]> {
+  let Latency = 7;
+  let NumMicroOps = 2;
+}
+
+def Ampere1BWrite_7cyc_1XY_1Z : SchedWriteRes<[Ampere1BUnitXY, Ampere1BUnitZ]> {
+  let Latency = 7;
+  let NumMicroOps = 2;
+}
+
+def Ampere1BWrite_7cyc_4XY_4S_4Z : SchedWriteRes<[Ampere1BUnitXY, Ampere1BUnitXY,
+                                                  Ampere1BUnitXY, Ampere1BUnitXY,
+                                                  Ampere1BUnitS,  Ampere1BUnitS,
+                                                  Ampere1BUnitS,  Ampere1BUnitS,
+                                                  Ampere1BUnitZ,  Ampere1BUnitZ,
+                                                  Ampere1BUnitZ,  Ampere1BUnitZ]> {
+  let Latency = 7;
+  let NumMicroOps = 12;
+}
+
+def Ampere1BWrite_8cyc_1BS_1L : SchedWriteRes<[Ampere1BUnitBS, Ampere1BUnitL]> {
+  let Latency = 8;
+  let NumMicroOps = 2;
+}
+
+def Ampere1BWrite_8cyc_1BS_1XY : SchedWriteRes<[Ampere1BUnitBS, Ampere1BUnitXY]> {
+  let Latency = 8;
+  let NumMicroOps = 2;
+}
+
+def Ampere1BWrite_8cyc_2XY : SchedWriteRes<[Ampere1BUnitXY, Ampere1BUnitXY]> {
+  let Latency = 8;
+  let NumMicroOps = 2;
+}
+
+def Ampere1BWrite_8cyc_4XY : SchedWriteRes<[Ampere1BUnitXY, Ampere1BUnitXY,
+                                            Ampere1BUnitXY, Ampere1BUnitXY]> {
+  let Latency = 8;
+  let NumMicroOps = 4;
+}
+
+def Ampere1BWrite_9cyc_6XY_4S_4Z : SchedWriteRes<[Ampere1BUnitXY, Ampere1BUnitXY,
+                                                  Ampere1BUnitXY, Ampere1BUnitXY,
+                                                  Ampere1BUnitXY, Ampere1BUnitXY,
+                                                  Ampere1BUnitS,  Ampere1BUnitS,
+                                                  Ampere1BUnitS,  Ampere1BUnitS,
+                                                  Ampere1BUnitZ,  Ampere1BUnitZ,
+                                                  Ampere1BUnitZ,  Ampere1BUnitZ]> {
+  let Latency = 9;
+  let NumMicroOps = 14;
+}
+
+def Ampere1BWrite_9cyc_1A_1BS_1X : SchedWriteRes<[Ampere1BUnitA, Ampere1BUnitBS, Ampere1BUnitX]> {
+  let Latency = 9;
+  let NumMicroOps = 3;
+}
+
+def Ampere1BWrite_9cyc_1A_1BS_1XY : SchedWriteRes<[Ampere1BUnitA, Ampere1BUnitBS, Ampere1BUnitXY]> {
+  let Latency = 9;
+  let NumMicroOps = 3;
+}
+
+def Ampere1BWrite_9cyc_1X : SchedWriteRes<[Ampere1BUnitX]> {
+  let Latency = 9;
+  let NumMicroOps = 1;
+}
+
+def Ampere1BWrite_9cyc_3XY : SchedWriteRes<[Ampere1BUnitXY, Ampere1BUnitXY, Ampere1BUnitXY]> {
+  let Latency = 9;
+  let NumMicroOps = 3;
+}
+
+def Ampere1BWrite_11cyc_1BS_2XY : SchedWriteRes<[Ampere1BUnitBS, Ampere1BUnitXY, Ampere1BUnitXY]> {
+  let Latency = 11;
+  let NumMicroOps = 3;
+}
+
+def Ampere1BWrite_12cyc_1X : SchedWriteRes<[Ampere1BUnitX]> {
+  let Latency = 12;
+  let NumMicroOps = 1;
+}
+
+def Ampere1BWrite_13cyc_1BS_1X : SchedWriteRes<[Ampere1BUnitBS, Ampere1BUnitX]> {
+  let Latency = 13;
+  let NumMicroOps = 2;
+}
+
+def Ampere1BWrite_17cyc_1X : SchedWriteRes<[Ampere1BUnitX]> {
+  let Latency = 17;
+  let NumMicroOps = 1;
+}
+
+def Ampere1BWrite_19cyc_2BS_1X : SchedWriteRes<[Ampere1BUnitBS,
+                                                Ampere1BUnitBS,
+                                                Ampere1BUnitX]> {
+  let Latency = 13;
+  let NumMicroOps = 3;
+}
+
+def Ampere1BWrite_19cyc_1X : SchedWriteRes<[Ampere1BUnitX]> {
+  let Latency = 19;
+  let NumMicroOps = 1;
+}
+
+def Ampere1BWrite_21cyc_1X : SchedWriteRes<[Ampere1BUnitX]> {
+  let Latency = 21;
+  let NumMicroOps = 1;
+}
+
+def Ampere1BWrite_33cyc_1X : SchedWriteRes<[Ampere1BUnitX]> {
+  let Latency = 33;
+  let NumMicroOps = 1;
+}
+
+def Ampere1BWrite_39cyc_1X : SchedWriteRes<[Ampere1BUnitX]> {
+  let Latency = 39;
+  let NumMicroOps = 1;
+}
+
+def Ampere1BWrite_63cyc_1X : SchedWriteRes<[Ampere1BUnitX]> {
+  let Latency = 63;
+  let NumMicroOps = 1;
+}
+
+// For basic arithmetic, we have more flexibility for short shifts (LSL shift <= 4),
+// which are a single uop, and for extended registers, which have full flexibility
+// across Unit A or B for both uops.
+def Ampere1BWrite_Arith : SchedWriteVariant<[
+                                SchedVar<RegExtendedPred, [Ampere1Write_2cyc_2AB]>,
+                                SchedVar<IsCheapLSL,      [Ampere1Write_1cyc_1AB]>,
+                                SchedVar<NoSchedPred,     [Ampere1Write_2cyc_1B_1AB]>]>;
+
+def Ampere1BWrite_ArithFlagsetting : SchedWriteVariant<[
+                                SchedVar<RegExtendedPred, [Ampere1Write_2cyc_2AB]>,
+                                SchedVar<IsCheapLSL,      [Ampere1Write_1cyc_1AB]>,
+                                SchedVar<NoSchedPred,     [Ampere1Write_2cyc_1B_1AB]>]>;
+
+//===----------------------------------------------------------------------===//
+// Map the target-defined scheduler read/write resources and latencies for Ampere-1.
+// This provides a coarse model, which is then specialised below.
+
+def : WriteRes<WriteImm,   [Ampere1BUnitAB]>;  // MOVN, MOVZ
+def : WriteRes<WriteI,     [Ampere1BUnitAB]>;  // ALU
+def : WriteRes<WriteISReg, [Ampere1BUnitB, Ampere1BUnitAB]> {
+  let Latency = 2;
+  let NumMicroOps = 2;
+}  // ALU of Shifted-Reg
+def : WriteRes<WriteIEReg, [Ampere1BUnitAB, Ampere1BUnitAB]> {
+  let Latency = 2;
+  let NumMicroOps = 2;
+}  // ALU of Extended-Reg
+def : WriteRes<WriteExtr,  [Ampere1BUnitB]>;  // EXTR shifts a reg pair
+def : WriteRes<WriteIS,    [Ampere1BUnitB]>;  // Shift/Scale
+def : WriteRes<WriteID32,  [Ampere1BUnitBS, Ampere1BUnitX]> {
+  let Latency = 13;
+}  // 32-bit Divide
+def : WriteRes<WriteID64,  [Ampere1BUnitBS, Ampere1BUnitX]> {
+  let Latency = 19;
+}  // 64-bit Divide
+def : WriteRes<WriteIM32,  [Ampere1BUnitBS]> {
+  let Latency = 3;
+}  // 32-bit Multiply
+def : WriteRes<WriteIM64,  [Ampere1BUnitBS, Ampere1UnitAB]> {
+  let Latency = 3;
+}  // 64-bit Multiply
+def : WriteRes<WriteBr,    [Ampere1BUnitA]>;
+def : WriteRes<WriteBrReg, [Ampere1BUnitA, Ampere1UnitA]>;
+def : WriteRes<WriteLD,    [Ampere1BUnitL]> {
+  let Latency = 3;
+}  // Load from base addr plus immediate offset
+def : WriteRes<WriteST,    [Ampere1BUnitS]> {
+  let Latency = 1;
+}  // Store to base addr plus immediate offset
+def : WriteRes<WriteSTP,   [Ampere1BUnitS, Ampere1BUnitS]> {
+  let Latency = 1;
+  let NumMicroOps = 1;
+}  // Store a register pair.
+def : WriteRes<WriteAdr,   [Ampere1BUnitAB]>;
+def : WriteRes<WriteLDIdx, [Ampere1BUnitAB, Ampere1BUnitS]> {
+  let Latency = 3;
+  let NumMicroOps = 1;
+}  // Load from a register index (maybe scaled).
+def : WriteRes<WriteSTIdx, [Ampere1BUnitS, Ampere1BUnitS]> {
+  let Latency = 1;
+  let NumMicroOps = 2;
+}  // Store to a register index (maybe scaled).
+def : WriteRes<WriteF,  [Ampere1BUnitXY]> {
+  let Latency = 2;
+}  // General floating-point ops.
+def : WriteRes<WriteFCmp,  [Ampere1BUnitX]> {
+  let Latency = 3;
+}  // Floating-point compare.
+def : WriteRes<WriteFCvt,  [Ampere1BUnitXY]> {
+  let Latency = 3;
+}  // Float conversion.
+def : WriteRes<WriteFCopy, [Ampere1BUnitXY]> {
+}  // Float-int register copy.
+def : WriteRes<WriteFImm,  [Ampere1BUnitXY]> {
+  let Latency = 2;
+}  // Float-int register copy.
+def : WriteRes<WriteFMul,  [Ampere1BUnitXY]> {
+  let Latency = 4;
+}  // Floating-point multiply.
+def : WriteRes<WriteFDiv,  [Ampere1BUnitXY]> {
+  let Latency = 19;
+}  // Floating-point division.
+def : WriteRes<WriteVd,    [Ampere1BUnitXY]> {
+  let Latency = 3;
+}  // 64bit Vector D ops.
+def : WriteRes<WriteVq,    [Ampere1BUnitXY]> {
+  let Latency = 3;
+}  // 128bit Vector Q ops.
+def : WriteRes<WriteVLD,   [Ampere1BUnitL, Ampere1BUnitL]> {
+  let Latency = 4;
+}  // Vector loads.
+def : WriteRes<WriteVST,   [Ampere1BUnitS, Ampere1BUnitZ]> {
+  let Latency = 2;
+}  // Vector stores.
+
+def : WriteRes<WriteAtomic,  []> { let Unsupported = 1; }
+
+def : WriteRes<WriteSys,     []> { let Latency = 1; }
+def : WriteRes<WriteBarrier, []> { let Latency = 1; }
+def : WriteRes<WriteHint,    []> { let Latency = 1; }
+
+def : WriteRes<WriteLDHi,    []> {
+  let Latency = 3;
+}  // The second register of a load-pair: LDP,LDPSW,LDNP,LDXP,LDAXP
+
+// Forwarding logic.
+def : ReadAdvance<ReadI,       0>;
+def : ReadAdvance<ReadISReg,   0>;
+def : ReadAdvance<ReadIEReg,   0>;
+def : ReadAdvance<ReadIM,      0>;
+def : ReadAdvance<ReadIMA,     1, [WriteIM32, WriteIM64]>;
+def : ReadAdvance<ReadID,      0>;
+def : ReadAdvance<ReadExtrHi,  0>;
+def : ReadAdvance<ReadST,      0>;
+def : ReadAdvance<ReadAdrBase, 0>;
+def : ReadAdvance<ReadVLD,     0>;
+
+//===----------------------------------------------------------------------===//
+// Specialising the scheduling model further for Ampere-1B.
+
+def : InstRW<[Ampere1BWrite_1cyc_1AB], (instrs COPY)>;
+
+// Branch instructions
+def : InstRW<[Ampere1BWrite_1cyc_1A], (instrs Bcc, BL, RET)>;
+def : InstRW<[Ampere1BWrite_1cyc_1A],
+        (instrs CBZW, CBZX, CBNZW, CBNZX, TBZW...
[truncated]

[ptomsich]

Just noticed another consistency check failing in the testsuite that my build did not show.
I'll work backwards from the build log to figure out what is missing from my local builds.

[davemgreen]

Also -We have found the tests like llvm/test/tools/llvm-mca/AArch64/Neoverse/N1-basic-instructions.s very useful in the past for visualizing the details in the model and making sure all the values are complete. It doesn't look like a similar test was added for the Ampere1, but you might find it useful to add some like it in this case.

[davemgreen]

Thanks. This LGTM if you can update the formatting.