[PATCH] D137925: [AArch64] FNMUL

[Sjoerd Meijer via Phabricator via llvm-commits]

SjoerdMeijer created this revision.
SjoerdMeijer added reviewers: dmgreen, david-arm, fhahn, cameron.mcinally, rscottmanley, madhur13490.
Herald added subscribers: hiraditya, kristof.beyls.
Herald added a project: All.
SjoerdMeijer requested review of this revision.
Herald added a project: LLVM.

This adds match patterns for the reassociated forms of FNMUL.


https://reviews.llvm.org/D137925

Files:
  llvm/lib/Target/AArch64/AArch64InstrInfo.td
  llvm/test/CodeGen/AArch64/fnmul.ll


Index: llvm/test/CodeGen/AArch64/fnmul.ll
===================================================================
--- /dev/null
+++ llvm/test/CodeGen/AArch64/fnmul.ll
@@ -0,0 +1,56 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+;RUN: llc < %s -mtriple=aarch64-none-linux-gnu -mattr=+v8.2a,+fullfp16 -fp-contract=fast -verify-machineinstrs -global-isel=0 | FileCheck %s
+;RUN: llc < %s -mtriple=aarch64-none-linux-gnu -mattr=+v8.2a,+fullfp16 -fp-contract=fast -verify-machineinstrs -global-isel=0 -enable-sign-dependent-rounding-fp-math=1 | FileCheck %s --check-prefix=NEGMUL
+;RUN: llc < %s -mtriple=aarch64-none-linux-gnu -mattr=+v8.2a,+fullfp16 -verify-machineinstrs -global-isel=0 -enable-sign-dependent-rounding-fp-math=1 | FileCheck %s --check-prefix=NEGMUL
+
+
+define half @fnmul16(half noundef %x, half noundef %y)  {
+; CHECK-LABEL: fnmul16:
+; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    fnmul h0, h0, h1
+; CHECK-NEXT:    ret
+;
+; NEGMUL-LABEL: fnmul16:
+; NEGMUL:       // %bb.0: // %entry
+; NEGMUL-NEXT:    fneg h0, h0
+; NEGMUL-NEXT:    fmul h0, h0, h1
+; NEGMUL-NEXT:    ret
+entry:
+  %fneg = fneg fast half %x
+  %mul = fmul fast half %fneg, %y
+  ret half %mul
+}
+
+define float @fnmul32(float noundef %x, float noundef %y)  {
+; CHECK-LABEL: fnmul32:
+; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    fnmul s0, s0, s1
+; CHECK-NEXT:    ret
+;
+; NEGMUL-LABEL: fnmul32:
+; NEGMUL:       // %bb.0: // %entry
+; NEGMUL-NEXT:    fneg s0, s0
+; NEGMUL-NEXT:    fmul s0, s0, s1
+; NEGMUL-NEXT:    ret
+entry:
+  %fneg = fneg fast float %x
+  %mul = fmul fast float %fneg, %y
+  ret float %mul
+}
+
+define double @fnmul64(double noundef %x, double noundef %y)  {
+; CHECK-LABEL: fnmul64:
+; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    fnmul d0, d0, d1
+; CHECK-NEXT:    ret
+;
+; NEGMUL-LABEL: fnmul64:
+; NEGMUL:       // %bb.0: // %entry
+; NEGMUL-NEXT:    fneg d0, d0
+; NEGMUL-NEXT:    fmul d0, d0, d1
+; NEGMUL-NEXT:    ret
+entry:
+  %fneg = fneg fast double %x
+  %mul = fmul fast double %fneg, %y
+  ret double %mul
+}
Index: llvm/lib/Target/AArch64/AArch64InstrInfo.td
===================================================================
--- llvm/lib/Target/AArch64/AArch64InstrInfo.td
+++ llvm/lib/Target/AArch64/AArch64InstrInfo.td
@@ -4170,6 +4170,17 @@
 }
 defm FSUB   : TwoOperandFPData<0b0011, "fsub", any_fsub>;
 
+// Match reassociated forms only if not sign dependent rounding.
+def : Pat<(fmul (fneg FPR16:$a), (f16 FPR16:$b)),
+          (FNMULHrr FPR16:$a, FPR16:$b)>,
+          Requires<[HasFullFP16,NoHonorSignDependentRounding]>;
+def : Pat<(fmul (fneg FPR32:$a), (f32 FPR32:$b)),
+          (FNMULSrr FPR32:$a, FPR32:$b)>,
+          Requires<[NoHonorSignDependentRounding]>;
+def : Pat<(fmul (fneg FPR64:$a), (f64 FPR64:$b)),
+          (FNMULDrr FPR64:$a, FPR64:$b)>,
+          Requires<[NoHonorSignDependentRounding]>;
+
 def : Pat<(v1f64 (fmaximum (v1f64 FPR64:$Rn), (v1f64 FPR64:$Rm))),
           (FMAXDrr FPR64:$Rn, FPR64:$Rm)>;
 def : Pat<(v1f64 (fminimum (v1f64 FPR64:$Rn), (v1f64 FPR64:$Rm))),


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