[X86] __builtin_cpu_supports: support x86-64{,-v2,-v3,-v4}

GCC 12 (https://gcc.gnu.org/PR101696) allows
__builtin_cpu_supports("x86-64") (and -v2 -v3 -v4).
This patch ports the feature.

* Add `FEATURE_X86_64_{BASELINE,V2,V3,V4}` to enum ProcessorFeatures,
  but keep CPU_FEATURE_MAX unchanged to make
  FeatureInfos/FeatureInfos_WithPLUS happy.
* Change validateCpuSupports to allow `x86-64{,-v2,-v3,-v4}`
* Change getCpuSupportsMask to return `std::array<uint32_t, 4>` where
  `x86-64{,-v2,-v3,-v4}` set bits `FEATURE_X86_64_{BASELINE,V2,V3,V4}`.
* `target("x86-64")` and `cpu_dispatch(x86_64)` are invalid. Tested by commit 9de3b35ac9159d5bae6e6796cb91e4f877a07189

Close https://github.com/llvm/llvm-project/issues/59961

Reviewed By: pengfei

Differential Revision: https://reviews.llvm.org/D158811

1 files changed, 5 insertions, 17 deletions

diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp
index 7b456ed..bf83171 100644
--- a/clang/lib/CodeGen/CodeGenFunction.cpp
+++ b/clang/lib/CodeGen/CodeGenFunction.cpp
@@ -2683,24 +2683,12 @@ llvm::Value *CodeGenFunction::FormX86ResolverCondition(
 
   if (!RO.Conditions.Architecture.empty()) {
     StringRef Arch = RO.Conditions.Architecture;
-    std::array<uint32_t, 4> Mask{};
-    // If arch= specifies an x86-64 micro-architecture level, test a special
-    // feature named FEATURE_X86_64_*, otherwise we use __builtin_cpu_is.
-    if (Arch.consume_front("x86-64")) {
-      if (Arch.empty()) // FEATURE_X86_64_BASELINE 95=2*32+31
-        Mask[2] = 1u << 31;
-      else if (Arch == "-v2") // FEATURE_X86_64_V2 96==3*32+0
-        Mask[3] = 1u << 0;
-      else if (Arch == "-v3") // FEATURE_X86_64_V3 97==3*32+1
-        Mask[3] = 1u << 1;
-      else if (Arch == "-v4") // FEATURE_X86_64_V3 98==3*32+2
-        Mask[3] = 1u << 2;
-      else
-        llvm_unreachable("invalid x86-64 micro-architecture level");
-      Condition = EmitX86CpuSupports(Mask);
-    } else {
+    // If arch= specifies an x86-64 micro-architecture level, test the feature
+    // with __builtin_cpu_supports, otherwise use __builtin_cpu_is.
+    if (Arch.starts_with("x86-64"))
+      Condition = EmitX86CpuSupports({Arch});
+    else
       Condition = EmitX86CpuIs(Arch);
-    }
   }
 
   if (!RO.Conditions.Features.empty()) {