[llvm-branch-commits] [clang] [llvm] [SPARC] Prefer RDPC over CALL to implement GETPCX for 64-bit target (PR #77196)

[Sergei Barannikov via llvm-branch-commits]

================
@@ -0,0 +1,51 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc < %s -relocation-model=pic -mtriple=sparc | FileCheck --check-prefix=SPARC %s
+; RUN: llc < %s -relocation-model=pic -mtriple=sparcv9 | FileCheck --check-prefix=SPARC64 %s
+
+;; SPARC32 and SPARC64 for classic UltraSPARCs implement GETPCX
+;; with a fake `call`.
+;; All other SPARC64 targets implement it with `rd %pc, %o7`.
+;; Need to do the tests in separate files because apparently `tune-cpu`
+;; attribute applies to the entire file at once.
+
+ at value = external global i32
+
+define i32 @testCall() nounwind #0 {
+; SPARC-LABEL: testCall:
+; SPARC:       ! %bb.0:
+; SPARC-NEXT:    save %sp, -96, %sp
+; SPARC-NEXT:  .Ltmp0:
+; SPARC-NEXT:    call .Ltmp1
+; SPARC-NEXT:  .Ltmp2:
+; SPARC-NEXT:    sethi %hi(_GLOBAL_OFFSET_TABLE_+(.Ltmp2-.Ltmp0)), %i0
+; SPARC-NEXT:  .Ltmp1:
+; SPARC-NEXT:    or %i0, %lo(_GLOBAL_OFFSET_TABLE_+(.Ltmp1-.Ltmp0)), %i0
+; SPARC-NEXT:    add %i0, %o7, %i0
+; SPARC-NEXT:    sethi %hi(value), %i1
+; SPARC-NEXT:    add %i1, %lo(value), %i1
+; SPARC-NEXT:    ld [%i0+%i1], %i0
+; SPARC-NEXT:    ld [%i0], %i0
+; SPARC-NEXT:    ret
+; SPARC-NEXT:    restore
+;
+; SPARC64-LABEL: testCall:
+; SPARC64:       ! %bb.0:
+; SPARC64-NEXT:    save %sp, -128, %sp
+; SPARC64-NEXT:  .Ltmp0:
+; SPARC64-NEXT:    call .Ltmp1
+; SPARC64-NEXT:  .Ltmp2:
+; SPARC64-NEXT:    sethi %hi(_GLOBAL_OFFSET_TABLE_+(.Ltmp2-.Ltmp0)), %i0
+; SPARC64-NEXT:  .Ltmp1:
+; SPARC64-NEXT:    or %i0, %lo(_GLOBAL_OFFSET_TABLE_+(.Ltmp1-.Ltmp0)), %i0
+; SPARC64-NEXT:    add %i0, %o7, %i0
+; SPARC64-NEXT:    sethi %hi(value), %i1
+; SPARC64-NEXT:    add %i1, %lo(value), %i1
+; SPARC64-NEXT:    ldx [%i0+%i1], %i0
+; SPARC64-NEXT:    ld [%i0], %i0
+; SPARC64-NEXT:    ret
+; SPARC64-NEXT:    restore
+  %1 = load i32, i32* @value
----------------
s-barannikov wrote:

```suggestion
  %1 = load i32, ptr @value
```
I thought it does not compile anymore :thinking: 

https://github.com/llvm/llvm-project/pull/77196