[clang] [PPC] Disable vsx and altivec when -msoft-float is used (PR #100450)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-clang

@llvm/pr-subscribers-backend-powerpc

Author: Zaara Syeda (syzaara)

<details>
<summary>Changes</summary>

We emit an error when -msoft-float and -maltivec/-mvsx is used together, but when -msoft-float is used on its own, there is still +altivec and +vsx in the IR attributes. This patch disables altivec and vsx when -msoft-float is used.

---
Full diff: https://github.com/llvm/llvm-project/pull/100450.diff


2 Files Affected:

- (modified) clang/lib/Basic/Targets/PPC.cpp (+5) 
- (added) clang/test/Driver/ppc-soft-float.c (+13) 


``````````diff
diff --git a/clang/lib/Basic/Targets/PPC.cpp b/clang/lib/Basic/Targets/PPC.cpp
index 9ff54083c923b..2b25cb189279a 100644
--- a/clang/lib/Basic/Targets/PPC.cpp
+++ b/clang/lib/Basic/Targets/PPC.cpp
@@ -690,6 +690,11 @@ bool PPCTargetInfo::initFeatureMap(
     return false;
   }
 
+  if (llvm::is_contained(FeaturesVec, "-hard-float")) {
+    Features["altivec"] = false;
+    Features["vsx"] = false;
+  }
+
   return TargetInfo::initFeatureMap(Features, Diags, CPU, FeaturesVec);
 }
 
diff --git a/clang/test/Driver/ppc-soft-float.c b/clang/test/Driver/ppc-soft-float.c
new file mode 100644
index 0000000000000..7b9205662ffeb
--- /dev/null
+++ b/clang/test/Driver/ppc-soft-float.c
@@ -0,0 +1,13 @@
+// RUN: %clang -target powerpc64-unknown-unknown -mcpu=pwr10 -msoft-float -S -emit-llvm %s -o - | FileCheck %s -check-prefix=CHECKSOFT
+// RUN: %clang -target powerpc64-unknown-unknown -mcpu=pwr10 -S -emit-llvm %s -o - | FileCheck %s -check-prefix=CHECKNOSOFT
+
+int main () {
+  return 0;
+}
+
+// CHECKSOFT-DAG: -hard-float
+// CHECKSOFT-DAG: -vsx
+// CHECKSOFT-DAG: -altivec
+
+// CHECKNOSOFT-DAG: +vsx
+// CHECKNOSOFT-DAG: +altivec

``````````

</details>


https://github.com/llvm/llvm-project/pull/100450