[AArch64] Enable AvoidLDAPUR for cpu=generic between armv8.4 and armv9.3. (#125261)

As added in #124274, CPUs in this range can suffer from performance
issues with ldapur. As the gain from ldar->ldapr is expected to be
greater than the minor gain from ldapr->ldapur, this opts to avoid the
instruction under the default -mcpu=generic when the -march is less that
armv8.8 / armv9.3.

I renamed AArch64Subtarget::Others to AArch64Subtarget::Generic to be
clearer what it means.

Author: davemgreen

llvm/lib/Target/AArch64/AArch64Subtarget.cpp

@@ -130,7 +130,12 @@ void AArch64Subtarget::initializeProperties(bool HasMinSize) {
   // this in the future so we can specify it together with the subtarget
   // features.
   switch (ARMProcFamily) {
-  case Others:
+  case Generic:
+    // Using TuneCPU=generic we avoid ldapur instructions to line up with the
+    // cpus that use the AvoidLDAPUR feature. We don't want this to be on
+    // forever, so it is enabled between armv8.4 and armv8.7/armv9.2.
+    if (hasV8_4aOps() && !hasV8_8aOps())
+      AvoidLDAPUR = true;
     break;
   case Carmel:
     CacheLineSize = 64;

llvm/lib/Target/AArch64/AArch64Subtarget.h

@@ -38,15 +38,15 @@ class Triple;
 class AArch64Subtarget final : public AArch64GenSubtargetInfo {
 public:
   enum ARMProcFamilyEnum : uint8_t {
-    Others,
+    Generic,
 #define ARM_PROCESSOR_FAMILY(ENUM) ENUM,
 #include "llvm/TargetParser/AArch64TargetParserDef.inc"
 #undef ARM_PROCESSOR_FAMILY
   };
 
 protected:
   /// ARMProcFamily - ARM processor family: Cortex-A53, Cortex-A57, and others.
-  ARMProcFamilyEnum ARMProcFamily = Others;
+  ARMProcFamilyEnum ARMProcFamily = Generic;
 
   // Enable 64-bit vectorization in SLP.
   unsigned MinVectorRegisterBitWidth = 64;

llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp

@@ -4282,7 +4282,7 @@ void AArch64TTIImpl::getUnrollingPreferences(Loop *L, ScalarEvolution &SE,
   // If mcpu is omitted, getProcFamily() returns AArch64Subtarget::Others, so by
   // checking for that case, we can ensure that the default behaviour is
   // unchanged
-  if (ST->getProcFamily() != AArch64Subtarget::Others &&
+  if (ST->getProcFamily() != AArch64Subtarget::Generic &&
       !ST->getSchedModel().isOutOfOrder()) {
     UP.Runtime = true;
     UP.Partial = true;

llvm/test/CodeGen/AArch64/Atomics/aarch64-atomic-load-rcpc_immo.ll

@@ -1,12 +1,15 @@
 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --filter-out "(?!^\s*lda.*\bsp\b)^\s*.*\bsp\b" --filter "^\s*(ld|st[^r]|swp|cas|bl|add|and|eor|orn|orr|sub|mvn|sxt|cmp|ccmp|csel|dmb)"
-; RUN: llc %s -o - -verify-machineinstrs -mtriple=aarch64 -mattr=+v8.4a -mattr=+rcpc-immo -global-isel=true -global-isel-abort=2 -O0 | FileCheck %s --check-prefixes=CHECK,GISEL
-; RUN: llc %s -o - -verify-machineinstrs -mtriple=aarch64 -mattr=+v8.4a -mattr=+rcpc-immo -global-isel=false -O1 | FileCheck %s --check-prefixes=CHECK,SDAG,SDAG-NOAVOIDLDAPUR
+; RUN: llc %s -o - -verify-machineinstrs -mtriple=aarch64 -mattr=+v8.8a -mattr=+rcpc-immo -global-isel=true -global-isel-abort=2 -O0 | FileCheck %s --check-prefixes=CHECK,GISEL
+; RUN: llc %s -o - -verify-machineinstrs -mtriple=aarch64 -mattr=+v8.4a -mattr=+rcpc-immo -global-isel=false -O1 | FileCheck %s --check-prefixes=CHECK,SDAG,SDAG-AVOIDLDAPUR
 ; RUN: llc %s -o - -verify-machineinstrs -mtriple=aarch64 -mattr=+v8.4a -mattr=+rcpc-immo,avoid-ldapur -global-isel=false -O1 | FileCheck %s --check-prefixes=CHECK,SDAG,SDAG-AVOIDLDAPUR
 ; RUN: llc %s -o - -verify-machineinstrs -mtriple=aarch64 -mcpu=neoverse-v2 -global-isel=false -O1 | FileCheck %s --check-prefixes=CHECK,SDAG,SDAG-AVOIDLDAPUR
 ; RUN: llc %s -o - -verify-machineinstrs -mtriple=aarch64 -mcpu=neoverse-v3 -global-isel=false -O1 | FileCheck %s --check-prefixes=CHECK,SDAG,SDAG-AVOIDLDAPUR
 ; RUN: llc %s -o - -verify-machineinstrs -mtriple=aarch64 -mcpu=cortex-x3 -global-isel=false -O1 | FileCheck %s --check-prefixes=CHECK,SDAG,SDAG-AVOIDLDAPUR
 ; RUN: llc %s -o - -verify-machineinstrs -mtriple=aarch64 -mcpu=cortex-x4 -global-isel=false -O1 | FileCheck %s --check-prefixes=CHECK,SDAG,SDAG-AVOIDLDAPUR
 ; RUN: llc %s -o - -verify-machineinstrs -mtriple=aarch64 -mcpu=cortex-x925 -global-isel=false -O1 | FileCheck %s --check-prefixes=CHECK,SDAG,SDAG-AVOIDLDAPUR
+; RUN: llc %s -o - -verify-machineinstrs -mtriple=aarch64 -mattr=+v9a -global-isel=false -O1 | FileCheck %s --check-prefixes=CHECK,SDAG,SDAG-AVOIDLDAPUR
+; RUN: llc %s -o - -verify-machineinstrs -mtriple=aarch64 -mattr=+v8.8a -global-isel=false -O1 | FileCheck %s --check-prefixes=CHECK,SDAG,SDAG-NOAVOIDLDAPUR
+; RUN: llc %s -o - -verify-machineinstrs -mtriple=aarch64 -mattr=+v9.3a -global-isel=false -O1 | FileCheck %s --check-prefixes=CHECK,SDAG,SDAG-NOAVOIDLDAPUR
 
 define i8 @load_atomic_i8_aligned_unordered(ptr %ptr) {
 ; CHECK-LABEL: load_atomic_i8_aligned_unordered: