[llvm] [AArch64] Combine vector FNEG+FMA into `FNML[A|S]` (PR #167900)

[Sander de Smalen via llvm-commits]

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@@ -0,0 +1,458 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 6
+; RUN: llc -mattr=+sve %s -o - | FileCheck %s --check-prefixes=CHECK
+; RUN: llc -mattr=+sme -force-streaming %s -o - | FileCheck %s --check-prefixes=CHECK
+
+target triple = "aarch64"
+
+define <vscale x 2 x double> @fmsub_nxv2f64(<vscale x 2 x double> %a, <vscale x 2 x double> %b, <vscale x 2 x double> %c) {
+; CHECK-LABEL: fmsub_nxv2f64:
+; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    ptrue p0.d
+; CHECK-NEXT:    fnmsb z0.d, p0/m, z1.d, z2.d
+; CHECK-NEXT:    ret
+entry:
+  %neg = fneg <vscale x 2 x double> %c
+  %0 = tail call <vscale x 2 x double> @llvm.fmuladd(<vscale x 2 x double> %a, <vscale x 2 x double> %b, <vscale x 2 x double> %neg)
+  ret <vscale x 2 x double> %0
+}
+
+define <vscale x 4 x float> @fmsub_nxv4f32(<vscale x 4 x float> %a, <vscale x 4 x float> %b, <vscale x 4 x float> %c) {
+; CHECK-LABEL: fmsub_nxv4f32:
+; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    ptrue p0.s
+; CHECK-NEXT:    fnmsb z0.s, p0/m, z1.s, z2.s
+; CHECK-NEXT:    ret
+entry:
+  %neg = fneg <vscale x 4 x float> %c
+  %0 = tail call <vscale x 4 x float> @llvm.fmuladd(<vscale x 4 x float> %a, <vscale x 4 x float> %b, <vscale x 4 x float> %neg)
+  ret <vscale x 4 x float> %0
+}
+
+define <vscale x 8 x half> @fmsub_nxv8f16(<vscale x 8 x half> %a, <vscale x 8 x half> %b, <vscale x 8 x half> %c) {
+; CHECK-LABEL: fmsub_nxv8f16:
+; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    ptrue p0.h
+; CHECK-NEXT:    fnmsb z0.h, p0/m, z1.h, z2.h
+; CHECK-NEXT:    ret
+entry:
+  %neg = fneg <vscale x 8 x half> %c
+  %0 = tail call <vscale x 8 x half> @llvm.fmuladd(<vscale x 8 x half> %a, <vscale x 8 x half> %b, <vscale x 8 x half> %neg)
+  ret <vscale x 8 x half> %0
+}
+
+define <2 x double> @fmsub_v2f64(<2 x double> %a, <2 x double> %b, <2 x double> %c) {
+; CHECK-LABEL: fmsub_v2f64:
+; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    ptrue p0.d, vl2
+; CHECK-NEXT:    // kill: def $q0 killed $q0 def $z0
+; CHECK-NEXT:    // kill: def $q2 killed $q2 def $z2
+; CHECK-NEXT:    // kill: def $q1 killed $q1 def $z1
+; CHECK-NEXT:    fnmsb z0.d, p0/m, z1.d, z2.d
+; CHECK-NEXT:    // kill: def $q0 killed $q0 killed $z0
+; CHECK-NEXT:    ret
+entry:
+  %neg = fneg <2 x double> %c
+  %0 = tail call <2 x double> @llvm.fmuladd(<2 x double> %a, <2 x double> %b, <2 x double> %neg)
+  ret <2 x double> %0
+}
+
+define <4 x float> @fmsub_v4f32(<4 x float> %a, <4 x float> %b, <4 x float> %c) {
+; CHECK-LABEL: fmsub_v4f32:
+; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    ptrue p0.s, vl4
+; CHECK-NEXT:    // kill: def $q0 killed $q0 def $z0
+; CHECK-NEXT:    // kill: def $q2 killed $q2 def $z2
+; CHECK-NEXT:    // kill: def $q1 killed $q1 def $z1
+; CHECK-NEXT:    fnmsb z0.s, p0/m, z1.s, z2.s
+; CHECK-NEXT:    // kill: def $q0 killed $q0 killed $z0
+; CHECK-NEXT:    ret
+entry:
+  %neg = fneg <4 x float> %c
+  %0 = tail call <4 x float> @llvm.fmuladd(<4 x float> %a, <4 x float> %b, <4 x float> %neg)
+  ret <4 x float> %0
+}
+
+define <8 x half> @fmsub_v8f16(<8 x half> %a, <8 x half> %b, <8 x half> %c) {
+; CHECK-LABEL: fmsub_v8f16:
+; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    ptrue p0.h, vl8
+; CHECK-NEXT:    // kill: def $q0 killed $q0 def $z0
+; CHECK-NEXT:    // kill: def $q2 killed $q2 def $z2
+; CHECK-NEXT:    // kill: def $q1 killed $q1 def $z1
+; CHECK-NEXT:    fnmsb z0.h, p0/m, z1.h, z2.h
+; CHECK-NEXT:    // kill: def $q0 killed $q0 killed $z0
+; CHECK-NEXT:    ret
+entry:
+  %neg = fneg <8 x half> %c
+  %0 = tail call <8 x half> @llvm.fmuladd(<8 x half> %a, <8 x half> %b, <8 x half> %neg)
+  ret <8 x half> %0
+}
+
+
+define <2 x double> @fmsub_flipped_v2f64(<2 x double> %c, <2 x double> %a, <2 x double> %b) {
+; CHECK-LABEL: fmsub_flipped_v2f64:
+; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    ptrue p0.d, vl2
+; CHECK-NEXT:    // kill: def $q0 killed $q0 def $z0
+; CHECK-NEXT:    // kill: def $q2 killed $q2 def $z2
+; CHECK-NEXT:    // kill: def $q1 killed $q1 def $z1
+; CHECK-NEXT:    fnmls z0.d, p0/m, z1.d, z2.d
+; CHECK-NEXT:    // kill: def $q0 killed $q0 killed $z0
+; CHECK-NEXT:    ret
+entry:
+  %neg = fneg <2 x double> %c
+  %0 = tail call <2 x double> @llvm.fmuladd(<2 x double> %a, <2 x double> %b, <2 x double> %neg)
+  ret <2 x double> %0
+}
+
+define <4 x float> @fmsub_flipped_v4f32(<4 x float> %c, <4 x float> %a, <4 x float> %b) {
+; CHECK-LABEL: fmsub_flipped_v4f32:
+; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    ptrue p0.s, vl4
+; CHECK-NEXT:    // kill: def $q0 killed $q0 def $z0
+; CHECK-NEXT:    // kill: def $q2 killed $q2 def $z2
+; CHECK-NEXT:    // kill: def $q1 killed $q1 def $z1
+; CHECK-NEXT:    fnmls z0.s, p0/m, z1.s, z2.s
+; CHECK-NEXT:    // kill: def $q0 killed $q0 killed $z0
+; CHECK-NEXT:    ret
+entry:
+  %neg = fneg <4 x float> %c
+  %0 = tail call <4 x float> @llvm.fmuladd(<4 x float> %a, <4 x float> %b, <4 x float> %neg)
+  ret <4 x float> %0
+}
+
+define <8 x half> @fmsub_flipped_v8f16(<8 x half> %c, <8 x half> %a, <8 x half> %b) {
+; CHECK-LABEL: fmsub_flipped_v8f16:
+; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    ptrue p0.h, vl8
+; CHECK-NEXT:    // kill: def $q0 killed $q0 def $z0
+; CHECK-NEXT:    // kill: def $q2 killed $q2 def $z2
+; CHECK-NEXT:    // kill: def $q1 killed $q1 def $z1
+; CHECK-NEXT:    fnmls z0.h, p0/m, z1.h, z2.h
+; CHECK-NEXT:    // kill: def $q0 killed $q0 killed $z0
+; CHECK-NEXT:    ret
+entry:
+  %neg = fneg <8 x half> %c
+  %0 = tail call <8 x half> @llvm.fmuladd(<8 x half> %a, <8 x half> %b, <8 x half> %neg)
+  ret <8 x half> %0
+}
+
+define <vscale x 2 x double> @fnmsub_nxv2f64(<vscale x 2 x double> %a, <vscale x 2 x double> %b, <vscale x 2 x double> %c) {
----------------
sdesmalen-arm wrote:

The name is wrong because this test actually generates an `fnmad`.

In general I find the tests a little confusing, because they're testing different things (not necessarily related to your PR). What about restructuring these tests a little bit so that we test *all* the types `<8 x half>`, `<4 x float>` and `<2 x double>` with the `fneg` on each of the operands (a, b, c).

If you want to test the cases for flipping the operands (resulting in a different instructions), then name those with 'commutative' and only test them for one single type of(e.g. `<vscale x 4 x float>`).

https://github.com/llvm/llvm-project/pull/167900