[clang] [X86] Support apxf in attribute target (PR #184078)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: Mikołaj Piróg (mikolaj-pirog)

<details>
<summary>Changes</summary>

As in title. This adds support for using apxf in attribute target. Individual features are not supported because they all share the same cpuid so we can't distinguish them -- now compiler emits error message instead of crashing.

Patch done with usage of Claude Code. I've verified that the output makes sense

---
Full diff: https://github.com/llvm/llvm-project/pull/184078.diff


3 Files Affected:

- (modified) clang/lib/Basic/Targets/X86.cpp (+26-8) 
- (modified) clang/test/CodeGen/attr-target-x86.c (+10) 
- (modified) clang/test/Sema/attr-target.c (+21) 


``````````diff
diff --git a/clang/lib/Basic/Targets/X86.cpp b/clang/lib/Basic/Targets/X86.cpp
index 6f88a428b1230..f0c31dddbc205 100644
--- a/clang/lib/Basic/Targets/X86.cpp
+++ b/clang/lib/Basic/Targets/X86.cpp
@@ -179,6 +179,31 @@ bool X86TargetInfo::initFeatureMap(
       continue;
     }
 
+    // Expand apxf to the individual APX features
+    if (Feature == "+apxf") {
+      UpdatedFeaturesVec.push_back("+egpr");
+      UpdatedFeaturesVec.push_back("+ndd");
+      UpdatedFeaturesVec.push_back("+ccmp");
+      UpdatedFeaturesVec.push_back("+nf");
+      UpdatedFeaturesVec.push_back("+zu");
+      if (!getTriple().isOSWindows()) {
+        UpdatedFeaturesVec.push_back("+push2pop2");
+        UpdatedFeaturesVec.push_back("+ppx");
+      }
+      continue;
+    }
+
+    if (Feature == "-apxf") {
+      UpdatedFeaturesVec.push_back("-egpr");
+      UpdatedFeaturesVec.push_back("-ndd");
+      UpdatedFeaturesVec.push_back("-ccmp");
+      UpdatedFeaturesVec.push_back("-nf");
+      UpdatedFeaturesVec.push_back("-zu");
+      UpdatedFeaturesVec.push_back("-push2pop2");
+      UpdatedFeaturesVec.push_back("-ppx");
+      continue;
+    }
+
     UpdatedFeaturesVec.push_back(Feature);
   }
 
@@ -1169,14 +1194,7 @@ bool X86TargetInfo::isValidFeatureName(StringRef Name) const {
       .Case("xsavec", true)
       .Case("xsaves", true)
       .Case("xsaveopt", true)
-      .Case("egpr", true)
-      .Case("push2pop2", true)
-      .Case("ppx", true)
-      .Case("ndd", true)
-      .Case("ccmp", true)
-      .Case("nf", true)
-      .Case("cf", true)
-      .Case("zu", true)
+      .Case("apxf", true)
       .Default(false);
 }
 
diff --git a/clang/test/CodeGen/attr-target-x86.c b/clang/test/CodeGen/attr-target-x86.c
index 474fa93629d89..35f07a2e0c2bb 100644
--- a/clang/test/CodeGen/attr-target-x86.c
+++ b/clang/test/CodeGen/attr-target-x86.c
@@ -19,6 +19,8 @@
 // CHECK: define {{.*}}@f_avx10_1{{.*}} [[f_avx10_1:#[0-9]+]]
 // CHECK: define {{.*}}@f_prefer_256_bit({{.*}} [[f_prefer_256_bit:#[0-9]+]]
 // CHECK: define {{.*}}@f_no_prefer_256_bit({{.*}} [[f_no_prefer_256_bit:#[0-9]+]]
+// CHECK: define {{.*}}@f_apxf({{.*}} [[f_apxf:#[0-9]+]]
+// CHECK: define {{.*}}@f_no_apxf({{.*}} [[f_no_apxf:#[0-9]+]]
 
 // CHECK: [[f_default]] = {{.*}}"target-cpu"="i686" "target-features"="+cmov,+cx8,+x87" "tune-cpu"="i686"
 void f_default(void) {}
@@ -108,3 +110,11 @@ void f_prefer_256_bit(void) {}
 // CHECK: [[f_no_prefer_256_bit]] = {{.*}}"target-features"="{{.*}}-prefer-256-bit
 __attribute__((target("no-prefer-256-bit")))
 void f_no_prefer_256_bit(void) {}
+
+// CHECK: [[f_apxf]] = {{.*}}"target-features"="{{.*}}+ccmp{{.*}}+egpr{{.*}}+ndd{{.*}}+nf{{.*}}+ppx{{.*}}+push2pop2{{.*}}+zu
+__attribute__((target("apxf")))
+void f_apxf(void) {}
+
+// CHECK: [[f_no_apxf]] = {{.*}}"target-features"="{{.*}}-ccmp{{.*}}-egpr{{.*}}-ndd{{.*}}-nf{{.*}}-ppx{{.*}}-push2pop2{{.*}}-zu
+__attribute__((target("no-apxf")))
+void f_no_apxf(void) {}
diff --git a/clang/test/Sema/attr-target.c b/clang/test/Sema/attr-target.c
index 65ece3c27d299..a68fb06ec8684 100644
--- a/clang/test/Sema/attr-target.c
+++ b/clang/test/Sema/attr-target.c
@@ -35,6 +35,27 @@ void __attribute__((target("x86-64-v2"))) v2(void) {}
 
 int __attribute__((target("sha"))) good_target_but_not_for_fmv() { return 5; }
 
+int __attribute__((target("apxf"))) apx_supported(void) { return 6; }
+int __attribute__((target("no-apxf"))) no_apx_supported(void) { return 7; }
+
+// APXF sub-features should NOT be supported directly in target attribute
+//expected-warning at +1 {{unsupported 'egpr' in the 'target' attribute string; 'target' attribute ignored}}
+int __attribute__((target("egpr"))) egpr_not_supported(void) { return 8; }
+//expected-warning at +1 {{unsupported 'ndd' in the 'target' attribute string; 'target' attribute ignored}}
+int __attribute__((target("ndd"))) ndd_not_supported(void) { return 9; }
+//expected-warning at +1 {{unsupported 'ccmp' in the 'target' attribute string; 'target' attribute ignored}}
+int __attribute__((target("ccmp"))) ccmp_not_supported(void) { return 10; }
+//expected-warning at +1 {{unsupported 'nf' in the 'target' attribute string; 'target' attribute ignored}}
+int __attribute__((target("nf"))) nf_not_supported(void) { return 11; }
+//expected-warning at +1 {{unsupported 'cf' in the 'target' attribute string; 'target' attribute ignored}}
+int __attribute__((target("cf"))) cf_not_supported(void) { return 12; }
+//expected-warning at +1 {{unsupported 'zu' in the 'target' attribute string; 'target' attribute ignored}}
+int __attribute__((target("zu"))) zu_not_supported(void) { return 13; }
+//expected-warning at +1 {{unsupported 'push2pop2' in the 'target' attribute string; 'target' attribute ignored}}
+int __attribute__((target("push2pop2"))) push2pop2_not_supported(void) { return 14; }
+//expected-warning at +1 {{unsupported 'ppx' in the 'target' attribute string; 'target' attribute ignored}}
+int __attribute__((target("ppx"))) ppx_not_supported(void) { return 15; }
+
 #elifdef __aarch64__
 
 int __attribute__((target("sve,arch=armv8-a"))) foo(void) { return 4; }

``````````

</details>


https://github.com/llvm/llvm-project/pull/184078