[llvm] [LTO] Set default Darwin CPU to apple-a7 for AArch64 (PR #81540)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-lto

Author: AtariDreams (AtariDreams)

<details>
<summary>Changes</summary>

Use apple-a7 as default for AArch64 Darwin targets that are not arm64e, as apple-a7 is the first AArch64 CPU that can run Darwin.

---
Full diff: https://github.com/llvm/llvm-project/pull/81540.diff


2 Files Affected:

- (modified) llvm/lib/LTO/LTOCodeGenerator.cpp (+3-2) 
- (modified) llvm/lib/LTO/ThinLTOCodeGenerator.cpp (+5-2) 


``````````diff
diff --git a/llvm/lib/LTO/LTOCodeGenerator.cpp b/llvm/lib/LTO/LTOCodeGenerator.cpp
index 52d8fff14be9ce..93fdde9c9b1d97 100644
--- a/llvm/lib/LTO/LTOCodeGenerator.cpp
+++ b/llvm/lib/LTO/LTOCodeGenerator.cpp
@@ -417,8 +417,9 @@ bool LTOCodeGenerator::determineTarget() {
       Config.CPU = "yonah";
     else if (Triple.isArm64e())
       Config.CPU = "apple-a12";
-    else if (Triple.getArch() == llvm::Triple::aarch64 ||
-             Triple.getArch() == llvm::Triple::aarch64_32)
+    else if (Triple.getArch() == llvm::Triple::aarch64)
+      Config.MCpu = "apple-a7";
+    else if (Triple.getArch() == llvm::Triple::aarch64_32)
       Config.CPU = "cyclone";
   }
 
diff --git a/llvm/lib/LTO/ThinLTOCodeGenerator.cpp b/llvm/lib/LTO/ThinLTOCodeGenerator.cpp
index 535faf5f780474..1c58cef5c3dc8d 100644
--- a/llvm/lib/LTO/ThinLTOCodeGenerator.cpp
+++ b/llvm/lib/LTO/ThinLTOCodeGenerator.cpp
@@ -546,8 +546,11 @@ static void initTMBuilder(TargetMachineBuilder &TMBuilder,
       TMBuilder.MCpu = "core2";
     else if (TheTriple.getArch() == llvm::Triple::x86)
       TMBuilder.MCpu = "yonah";
-    else if (TheTriple.getArch() == llvm::Triple::aarch64 ||
-             TheTriple.getArch() == llvm::Triple::aarch64_32)
+    else if (TheTriple.isArm64e())
+      TMBuilder.MCpu = "apple-a12";
+    else if (TheTriple.getArch() == llvm::Triple::aarch64)
+      TMBuilder.MCpu = "apple-a7";
+    else if (TheTriple.getArch() == llvm::Triple::aarch64_32)
       TMBuilder.MCpu = "cyclone";
   }
   TMBuilder.TheTriple = std::move(TheTriple);

``````````

</details>


https://github.com/llvm/llvm-project/pull/81540