[llvm] [SDAG] Avoid creating redundant stack slots when lowering FSINCOS (PR #108401)

[Matt Arsenault via llvm-commits]

================
@@ -0,0 +1,115 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
+; RUN: llc -mtriple=aarch64-linux-gnu -o - %s | FileCheck %s
+
+define { float, float } @sincos_f32_value_return(float %x) {
+; CHECK-LABEL: sincos_f32_value_return:
+; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    str x30, [sp, #-16]! // 8-byte Folded Spill
+; CHECK-NEXT:    .cfi_def_cfa_offset 16
+; CHECK-NEXT:    .cfi_offset w30, -16
+; CHECK-NEXT:    add x0, sp, #12
+; CHECK-NEXT:    add x1, sp, #8
+; CHECK-NEXT:    bl sincosf
+; CHECK-NEXT:    ldp s1, s0, [sp, #8]
+; CHECK-NEXT:    ldr x30, [sp], #16 // 8-byte Folded Reload
+; CHECK-NEXT:    ret
+entry:
+  %sin = tail call float @llvm.sin.f32(float %x)
+  %cos = tail call float @llvm.cos.f32(float %x)
+  %ret_0 = insertvalue { float, float } poison, float %sin, 0
+  %ret_1 = insertvalue { float, float } %ret_0, float %cos, 1
+  ret { float, float } %ret_1
+}
+
+define void @sincos_f32_ptr_return(float %x, ptr %out_sin, ptr %out_cos) {
+; CHECK-LABEL: sincos_f32_ptr_return:
+; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    str x30, [sp, #-16]! // 8-byte Folded Spill
+; CHECK-NEXT:    .cfi_def_cfa_offset 16
+; CHECK-NEXT:    .cfi_offset w30, -16
+; CHECK-NEXT:    bl sincosf
+; CHECK-NEXT:    ldr x30, [sp], #16 // 8-byte Folded Reload
+; CHECK-NEXT:    ret
+entry:
+  %sin = tail call float @llvm.sin.f32(float %x)
+  %cos = tail call float @llvm.cos.f32(float %x)
+  store float %sin, ptr %out_sin, align 4
+  store float %cos, ptr %out_cos, align 4
+  ret void
+}
+
+define float @sincos_f32_mixed_return(float %x, ptr %out_sin) {
+; CHECK-LABEL: sincos_f32_mixed_return:
+; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    str x30, [sp, #-16]! // 8-byte Folded Spill
+; CHECK-NEXT:    .cfi_def_cfa_offset 16
+; CHECK-NEXT:    .cfi_offset w30, -16
+; CHECK-NEXT:    add x1, sp, #12
+; CHECK-NEXT:    bl sincosf
+; CHECK-NEXT:    ldr s0, [sp, #12]
+; CHECK-NEXT:    ldr x30, [sp], #16 // 8-byte Folded Reload
+; CHECK-NEXT:    ret
+entry:
+  %sin = tail call float @llvm.sin.f32(float %x)
+  %cos = tail call float @llvm.cos.f32(float %x)
+  store float %sin, ptr %out_sin, align 4
+  ret float %cos
+}
+
+define { double, double } @sincos_f64_value_return(double %x) {
+; CHECK-LABEL: sincos_f64_value_return:
+; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    sub sp, sp, #32
+; CHECK-NEXT:    str x30, [sp, #16] // 8-byte Folded Spill
+; CHECK-NEXT:    .cfi_def_cfa_offset 32
+; CHECK-NEXT:    .cfi_offset w30, -16
+; CHECK-NEXT:    add x0, sp, #24
+; CHECK-NEXT:    add x1, sp, #8
+; CHECK-NEXT:    bl sincos
+; CHECK-NEXT:    ldr d0, [sp, #24]
+; CHECK-NEXT:    ldr d1, [sp, #8]
+; CHECK-NEXT:    ldr x30, [sp, #16] // 8-byte Folded Reload
+; CHECK-NEXT:    add sp, sp, #32
+; CHECK-NEXT:    ret
+entry:
+  %sin = tail call double @llvm.sin.f64(double %x)
+  %cos = tail call double @llvm.cos.f64(double %x)
+  %ret_0 = insertvalue { double, double } poison, double %sin, 0
+  %ret_1 = insertvalue { double, double } %ret_0, double %cos, 1
+  ret { double, double } %ret_1
+}
+
+define void @sincos_f64_ptr_return(double %x, ptr %out_sin, ptr %out_cos) {
+; CHECK-LABEL: sincos_f64_ptr_return:
+; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    str x30, [sp, #-16]! // 8-byte Folded Spill
+; CHECK-NEXT:    .cfi_def_cfa_offset 16
+; CHECK-NEXT:    .cfi_offset w30, -16
+; CHECK-NEXT:    bl sincos
+; CHECK-NEXT:    ldr x30, [sp], #16 // 8-byte Folded Reload
+; CHECK-NEXT:    ret
+entry:
+  %sin = tail call double @llvm.sin.f64(double %x)
+  %cos = tail call double @llvm.cos.f64(double %x)
+  store double %sin, ptr %out_sin, align 4
+  store double %cos, ptr %out_cos, align 4
+  ret void
+}
+
+define double @sincos_f64_mixed_return(double %x, ptr %out_sin) {
+; CHECK-LABEL: sincos_f64_mixed_return:
+; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    str x30, [sp, #-16]! // 8-byte Folded Spill
+; CHECK-NEXT:    .cfi_def_cfa_offset 16
+; CHECK-NEXT:    .cfi_offset w30, -16
+; CHECK-NEXT:    add x1, sp, #8
+; CHECK-NEXT:    bl sincos
+; CHECK-NEXT:    ldr d0, [sp, #8]
+; CHECK-NEXT:    ldr x30, [sp], #16 // 8-byte Folded Reload
+; CHECK-NEXT:    ret
+entry:
+  %sin = tail call double @llvm.sin.f64(double %x)
+  %cos = tail call double @llvm.cos.f64(double %x)
+  store double %sin, ptr %out_sin, align 4
+  ret double %cos
+}
----------------
arsenm wrote:

Needs negative test where one or both stores are volatile or atomic 

https://github.com/llvm/llvm-project/pull/108401