llvm: Match new LLVM 128-bit integer alignment on sparc

LLVM continues to align more 128-bit integers to 128-bits in the data
layout rather than relying on the high level language to do it. Update
SPARC target files to match and add a backcompat replacement for current
LLVMs.

See llvm/llvm-project#106951 for details

Author: maurer

compiler/rustc_codegen_llvm/src/context.rs

@@ -148,6 +148,11 @@ pub(crate) unsafe fn create_module<'ll>(
             target_data_layout =
                 target_data_layout.replace("-p270:32:32-p271:32:32-p272:64:64", "");
         }
+        if sess.target.arch.starts_with("sparc") {
+            // LLVM 20 updates the sparc layout to correctly align 128 bit integers to 128 bit.
+            // See https://github.com/llvm/llvm-project/pull/106951
+            target_data_layout = target_data_layout.replace("-i128:128", "");
+        }
     }
 
     // Ensure the data-layout values hardcoded remain the defaults.

compiler/rustc_target/src/spec/targets/sparc64_unknown_linux_gnu.rs

@@ -16,7 +16,7 @@ pub(crate) fn target() -> Target {
             std: Some(true),
         },
         pointer_width: 64,
-        data_layout: "E-m:e-i64:64-n32:64-S128".into(),
+        data_layout: "E-m:e-i64:64-i128:128-n32:64-S128".into(),
         arch: "sparc64".into(),
         options: base,
     }

compiler/rustc_target/src/spec/targets/sparc64_unknown_netbsd.rs

@@ -16,7 +16,7 @@ pub(crate) fn target() -> Target {
             std: Some(true),
         },
         pointer_width: 64,
-        data_layout: "E-m:e-i64:64-n32:64-S128".into(),
+        data_layout: "E-m:e-i64:64-i128:128-n32:64-S128".into(),
         arch: "sparc64".into(),
         options: TargetOptions { endian: Endian::Big, mcount: "__mcount".into(), ..base },
     }

compiler/rustc_target/src/spec/targets/sparc64_unknown_openbsd.rs

@@ -17,7 +17,7 @@ pub(crate) fn target() -> Target {
             std: Some(true),
         },
         pointer_width: 64,
-        data_layout: "E-m:e-i64:64-n32:64-S128".into(),
+        data_layout: "E-m:e-i64:64-i128:128-n32:64-S128".into(),
         arch: "sparc64".into(),
         options: base,
     }

compiler/rustc_target/src/spec/targets/sparc_unknown_linux_gnu.rs

@@ -11,7 +11,7 @@ pub(crate) fn target() -> Target {
             std: Some(true),
         },
         pointer_width: 32,
-        data_layout: "E-m:e-p:32:32-i64:64-f128:64-n32-S64".into(),
+        data_layout: "E-m:e-p:32:32-i64:64-i128:128-f128:64-n32-S64".into(),
         arch: "sparc".into(),
         options: TargetOptions {
             cpu: "v9".into(),

compiler/rustc_target/src/spec/targets/sparc_unknown_none_elf.rs

@@ -17,7 +17,7 @@ pub(crate) fn target() -> Target {
         ..Default::default()
     };
     Target {
-        data_layout: "E-m:e-p:32:32-i64:64-f128:64-n32-S64".into(),
+        data_layout: "E-m:e-p:32:32-i64:64-i128:128-f128:64-n32-S64".into(),
         llvm_target: "sparc-unknown-none-elf".into(),
         metadata: crate::spec::TargetMetadata {
             description: Some("Bare 32-bit SPARC V7+".into()),

compiler/rustc_target/src/spec/targets/sparcv9_sun_solaris.rs

@@ -19,7 +19,7 @@ pub(crate) fn target() -> Target {
             std: Some(true),
         },
         pointer_width: 64,
-        data_layout: "E-m:e-i64:64-n32:64-S128".into(),
+        data_layout: "E-m:e-i64:64-i128:128-n32:64-S128".into(),
         // Use "sparc64" instead of "sparcv9" here, since the former is already
         // used widely in the source base. If we ever needed ABI
         // differentiation from the sparc64, we could, but that would probably