[llvm] [WebAssembly] Lower fmuladd to madd and nmadd (PR #161355)

[Sam Parker via llvm-commits]

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@@ -2,9 +2,278 @@
 
 ; RUN: llc < %s -disable-wasm-fallthrough-return-opt -wasm-disable-explicit-locals -wasm-keep-registers  -mattr=+fp16,+simd128,+relaxed-simd | FileCheck %s --check-prefix=RELAXED
 ; RUN: llc < %s -disable-wasm-fallthrough-return-opt -wasm-disable-explicit-locals -wasm-keep-registers  -mattr=+fp16,+simd128,              | FileCheck %s --check-prefix=STRICT
+; RUN: llc < %s -disable-wasm-fallthrough-return-opt -wasm-disable-explicit-locals -wasm-keep-registers  -mattr=+simd128                     | FileCheck %s --check-prefix=NOFP16
+; RUN: llc < %s -disable-wasm-fallthrough-return-opt -wasm-disable-explicit-locals -wasm-keep-registers                                      | FileCheck %s --check-prefix=NOSIMD
 
 target triple = "wasm32"
 
+define half @fadd_fmul_contract_f16(half %a, half %b, half %c) {
+; RELAXED-LABEL: fadd_fmul_contract_f16:
+; RELAXED:         .functype fadd_fmul_contract_f16 (f32, f32, f32) -> (f32)
+; RELAXED-NEXT:  # %bb.0:
+; RELAXED-NEXT:    call $push0=, __truncsfhf2, $0
+; RELAXED-NEXT:    call $push1=, __extendhfsf2, $pop0
+; RELAXED-NEXT:    call $push2=, __truncsfhf2, $1
+; RELAXED-NEXT:    call $push3=, __extendhfsf2, $pop2
+; RELAXED-NEXT:    f32.mul $push4=, $pop1, $pop3
+; RELAXED-NEXT:    call $push5=, __truncsfhf2, $2
+; RELAXED-NEXT:    call $push6=, __extendhfsf2, $pop5
+; RELAXED-NEXT:    f32.add $push7=, $pop4, $pop6
+; RELAXED-NEXT:    return $pop7
+;
+; STRICT-LABEL: fadd_fmul_contract_f16:
+; STRICT:         .functype fadd_fmul_contract_f16 (f32, f32, f32) -> (f32)
+; STRICT-NEXT:  # %bb.0:
+; STRICT-NEXT:    call $push0=, __truncsfhf2, $0
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sparker-arm wrote:

I can only assume it will not stay as f16 but, as wasm doesn't have scalar fp16 support, returning an f32 appears to be the valid thing to do. 

https://github.com/llvm/llvm-project/pull/161355