[PATCH] D120158: [SelectionDAG][X86] Support f16 in getReciprocalOpName.

[Craig Topper via Phabricator via llvm-commits]

craig.topper created this revision.
craig.topper added reviewers: spatel, pengfei, RKSimon.
Herald added subscribers: ecnelises, hiraditya.
craig.topper requested review of this revision.
Herald added a project: LLVM.

If the "reciprocal-estimates" attribute is present and it doesn't
contain "all", "none", or "default", we previously crashed on f16
operations.

This patch addes an 'h' suffix' to prevent the crash.

I've added simple tests that just enable the estimate for all
vec-sqrt and one test case that explicitly tests the new 'h' suffix
to override the default steps.

There may be some frontend change needed to, but I haven't checked
that yet.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D120158

Files:
  llvm/lib/CodeGen/TargetLoweringBase.cpp
  llvm/test/CodeGen/X86/avx512fp16-intrinsics.ll


Index: llvm/test/CodeGen/X86/avx512fp16-intrinsics.ll
===================================================================
--- llvm/test/CodeGen/X86/avx512fp16-intrinsics.ll
+++ llvm/test/CodeGen/X86/avx512fp16-intrinsics.ll
@@ -35,6 +35,32 @@
   ret <32 x half> %2
 }
 
+define <32 x half> @test_sqrt_ph_512_fast_estimate_attribute(<32 x half> %a0, <32 x half> %a1) "reciprocal-estimates"="vec-sqrt" {
+; CHECK-LABEL: test_sqrt_ph_512_fast_estimate_attribute:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    vrsqrtph %zmm0, %zmm0
+; CHECK-NEXT:    vmulph %zmm0, %zmm1, %zmm0
+; CHECK-NEXT:    retq
+  %1 = call fast <32 x half> @llvm.sqrt.v32f16(<32 x half> %a0)
+  %2 = fdiv fast <32 x half> %a1, %1
+  ret <32 x half> %2
+}
+
+define <32 x half> @test_sqrt_ph_512_fast_estimate_attribute_2(<32 x half> %a0, <32 x half> %a1) "reciprocal-estimates"="vec-sqrth:1" {
+; CHECK-LABEL: test_sqrt_ph_512_fast_estimate_attribute_2:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    vrsqrtph %zmm0, %zmm2
+; CHECK-NEXT:    vmulph %zmm2, %zmm0, %zmm0
+; CHECK-NEXT:    vfmadd213ph {{\.?LCPI[0-9]+_[0-9]+}}(%rip){1to32}, %zmm2, %zmm0
+; CHECK-NEXT:    vmulph {{\.?LCPI[0-9]+_[0-9]+}}(%rip){1to32}, %zmm2, %zmm2
+; CHECK-NEXT:    vmulph %zmm1, %zmm0, %zmm0
+; CHECK-NEXT:    vmulph %zmm0, %zmm2, %zmm0
+; CHECK-NEXT:    retq
+  %1 = call fast <32 x half> @llvm.sqrt.v32f16(<32 x half> %a0)
+  %2 = fdiv fast <32 x half> %a1, %1
+  ret <32 x half> %2
+}
+
 define <32 x half> @test_mask_sqrt_ph_512(<32 x half> %a0, <32 x half> %passthru, i32 %mask) {
 ; CHECK-LABEL: test_mask_sqrt_ph_512:
 ; CHECK:       # %bb.0:
Index: llvm/lib/CodeGen/TargetLoweringBase.cpp
===================================================================
--- llvm/lib/CodeGen/TargetLoweringBase.cpp
+++ llvm/lib/CodeGen/TargetLoweringBase.cpp
@@ -2072,9 +2072,11 @@
 
   Name += IsSqrt ? "sqrt" : "div";
 
-  // TODO: Handle "half" or other float types?
+  // TODO: Handle other float types?
   if (VT.getScalarType() == MVT::f64) {
     Name += "d";
+  } else if (VT.getScalarType() == MVT::f16) {
+    Name += "h";
   } else {
     assert(VT.getScalarType() == MVT::f32 &&
            "Unexpected FP type for reciprocal estimate");


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