[clang] [X86][Driver] Do not add `-evex512` for `-march=native` when the targ… (PR #91694)

[Phoebe Wang via cfe-commits]

https://github.com/phoebewang created https://github.com/llvm/llvm-project/pull/91694

…et doesn't support AVX512

Users want `-march=sandybridge -mavx512f -mavx512vl` behaves the same as `-march=native -mavx512f -mavx512vl` on a sandybridge target.

Fixes: #91076

>From 6ea15aa0ee6726cad8dccff10155f058afa0f013 Mon Sep 17 00:00:00 2001
From: Phoebe Wang <phoebe.wang at intel.com>
Date: Fri, 10 May 2024 11:21:41 +0800
Subject: [PATCH] [X86][Driver] Do not add `-evex512` for `-march=native` when
 the target doesn't support AVX512

Users want `-march=sandybridge -mavx512f -mavx512vl` behaves the same as
`-march=native -mavx512f -mavx512vl` on a sandybridge target.

Fixes: #91076
---
 clang/lib/Driver/ToolChains/Arch/X86.cpp | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/clang/lib/Driver/ToolChains/Arch/X86.cpp b/clang/lib/Driver/ToolChains/Arch/X86.cpp
index 53e26a9f8e229..c6d97ef4e971a 100644
--- a/clang/lib/Driver/ToolChains/Arch/X86.cpp
+++ b/clang/lib/Driver/ToolChains/Arch/X86.cpp
@@ -132,10 +132,14 @@ void x86::getX86TargetFeatures(const Driver &D, const llvm::Triple &Triple,
   if (const Arg *A = Args.getLastArg(clang::driver::options::OPT_march_EQ)) {
     if (StringRef(A->getValue()) == "native") {
       llvm::StringMap<bool> HostFeatures;
-      if (llvm::sys::getHostCPUFeatures(HostFeatures))
-        for (auto &F : HostFeatures)
+      if (llvm::sys::getHostCPUFeatures(HostFeatures)) {
+        for (auto &F : HostFeatures) {
+          if (!F.second && F.first() == "evex512")
+            continue;
           Features.push_back(
               Args.MakeArgString((F.second ? "+" : "-") + F.first()));
+        }
+      }
     }
   }