[Codegen][ARM] Add float softening for cbrt

We would previously have no soft-float softening for cbrt, so could hit
a crash failing to select. This fills in what appears to be missing.

Differential Revision: https://reviews.llvm.org/D69345

2 files changed, 31 insertions, 0 deletions

diff --git a/llvm/test/CodeGen/ARM/fp16-promote.ll b/llvm/test/CodeGen/ARM/fp16-promote.ll
index 183653036f3..5c409350206 100644
--- a/llvm/test/CodeGen/ARM/fp16-promote.ll
+++ b/llvm/test/CodeGen/ARM/fp16-promote.ll
@@ -497,6 +497,21 @@ define void @test_pow(half* %p, half* %q) #0 {
   ret void
 }
 
+; CHECK-FP16-LABEL: test_cbrt:
+; CHECK-FP16: vcvtb.f32.f16
+; CHECK-FP16: bl powf
+; CHECK-FP16: vcvtb.f16.f32
+; CHECK-LIBCALL-LABEL: test_cbrt:
+; CHECK-LIBCALL: bl __aeabi_h2f
+; CHECK-LIBCALL: bl powf
+; CHECK-LIBCALL: bl __aeabi_f2h
+define void @test_cbrt(half* %p) #0 {
+  %a = load half, half* %p, align 2
+  %r = call half @llvm.pow.f16(half %a, half 0x3FD5540000000000)
+  store half %r, half* %p
+  ret void
+}
+
 ; CHECK-FP16-LABEL: test_exp:
 ; CHECK-FP16: vcvtb.f32.f16
 ; CHECK-FP16: bl expf
diff --git a/llvm/test/CodeGen/ARM/pow.ll b/llvm/test/CodeGen/ARM/pow.ll
index 2b3df92aab5..8abc37de3d4 100644
--- a/llvm/test/CodeGen/ARM/pow.ll
+++ b/llvm/test/CodeGen/ARM/pow.ll
@@ -26,6 +26,22 @@ define double @pow_f64_one_fourth_fmf(double %x) nounwind {
   ret double %r
 }
 
+define float @pow_f32_one_third_fmf(float %x) nounwind {
+; ANY-LABEL: pow_f32_one_third_fmf:
+; SOFTFLOAT:    bl cbrtf
+; HARDFLOAT:    b cbrtf
+  %r = call fast float @llvm.pow.f32(float %x, float 0x3FD5555560000000)
+  ret float %r
+}
+
+define double @pow_f64_one_third_fmf(double %x) nounwind {
+; ANY-LABEL: pow_f64_one_third_fmf:
+; SOFTFLOAT:    bl cbrt
+; HARDFLOAT:    b cbrt
+  %r = call fast double @llvm.pow.f64(double %x, double 0x3FD5555555555555)
+  ret double %r
+}
+
 define <4 x float> @pow_v4f32_one_fourth_fmf(<4 x float> %x) nounwind {
 ; ANY-LABEL: pow_v4f32_one_fourth_fmf:
 ; SOFTFLOAT:    bl powf