InstCombine: Add fma + fabs/fneg transforms

[arsenm]

Summary

fma (fneg x), (fneg y), z -> fma x, y, z
fma (fabs x), (fabs x), z -> fma x, x, z

[arsenm]

Remove unrelated test change

[majnemer]

lib/Transforms/InstCombine/InstCombineCalls.cpp

1568–1569

Formatting looks weird.

1579–1580

Formatting looks weird.

[arsenm]

clang-format

[arsenm]

ping

[majnemer]

LGTM

[arsenm]

r290859

lib/Transforms/InstCombine/InstCombineCalls.cpp

if (isa<ConstantFP>(Arg0) && !isa<ConstantFP>(Arg1)) {
       II->setArgOperand(0, Arg1);
       II->setArgOperand(1, Arg0);
       return II;
     }
     if (Value *V = simplifyMinnumMaxnum(*II))
       return replaceInstUsesWith(*II, V);
     break;
   }
+  case Intrinsic::fma:
+  case Intrinsic::fmuladd: {
+    Value *LHS = nullptr;
+    Value *RHS = nullptr;
+
+    Value *Src0 = II->getArgOperand(0);
+    Value *Src1 = II->getArgOperand(1);
+
+    // fma fneg(x), fneg(y), z -> fma x, y, z
+    if (match(Src0, m_FNeg(m_Value(LHS))) && match(Src1, m_FNeg(m_Value(RHS)))) {
+      CallInst *NewCall = Builder->CreateCall(II->getCalledFunction(),
+                                            { LHS, RHS, II->getArgOperand(2) });
+      NewCall->takeName(II);
+      NewCall->copyFastMathFlags(II);
+      return replaceInstUsesWith(*II, NewCall);
+    }
+
+    // fma fabs(x), fabs(x), z -> fma x, x, z
+    if (match(Src0, m_Intrinsic<Intrinsic::fabs>(m_Value(LHS))) &&
+        match(Src1, m_Intrinsic<Intrinsic::fabs>(m_Value(RHS))) &&
+        LHS == RHS) {
+      CallInst *NewCall = Builder->CreateCall(II->getCalledFunction(),
+                                             { LHS, LHS, II->getArgOperand(2) });
+      NewCall->takeName(II);
+      NewCall->copyFastMathFlags(II);
+      return replaceInstUsesWith(*II, NewCall);
+    }
+
+    break;
+  }
   case Intrinsic::ppc_altivec_lvx:
   case Intrinsic::ppc_altivec_lvxl:
     // Turn PPC lvx -> load if the pointer is known aligned.
     if (getOrEnforceKnownAlignment(II->getArgOperand(0), 16, DL, II,
                                    &DT) >= 16) {
       Value *Ptr = Builder->CreateBitCast(II->getArgOperand(0),
                                          PointerType::getUnqual(II->getType()));
       return new LoadInst(Ptr);

test/Transforms/InstCombine/fma.ll

+; RUN: opt -S -instcombine < %s | FileCheck %s
+
+declare float @llvm.fma.f32(float, float, float) #1
+declare float @llvm.fmuladd.f32(float, float, float) #1
+declare float @llvm.fabs.f32(float) #1
+
+@external = external global i32
+
+; CHECK-LABEL: @fma_fneg_x_fneg_y(
+; CHECK: %fma = call float @llvm.fma.f32(float %x, float %y, float %z)
+define float @fma_fneg_x_fneg_y(float %x, float %y, float %z) {
+  %x.fneg = fsub float -0.0, %x
+  %y.fneg = fsub float -0.0, %y
+  %fma = call float @llvm.fma.f32(float %x.fneg, float %y.fneg, float %z)
+  ret float %fma
+}
+
+; CHECK-LABEL: @fma_fneg_x_fneg_y_fast(
+; CHECK: %fma = call fast float @llvm.fma.f32(float %x, float %y, float %z)
+define float @fma_fneg_x_fneg_y_fast(float %x, float %y, float %z) {
+  %x.fneg = fsub float -0.0, %x
+  %y.fneg = fsub float -0.0, %y
+  %fma = call fast float @llvm.fma.f32(float %x.fneg, float %y.fneg, float %z)
+  ret float %fma
+}
+
+; CHECK-LABEL: @fma_fneg_const_fneg_y(
+; CHECK: %fma = call float @llvm.fma.f32(float bitcast (i32 ptrtoint (i32* @external to i32) to float), float %y, float %z)
+define float @fma_fneg_const_fneg_y(float %y, float %z) {
+  %y.fneg = fsub float -0.0, %y
+  %fma = call float @llvm.fma.f32(float fsub (float -0.0, float bitcast (i32 ptrtoint (i32* @external to i32) to float)), float %y.fneg, float %z)
+  ret float %fma
+}
+
+; CHECK-LABEL: @fma_fneg_x_fneg_const(
+; CHECK: %fma = call float @llvm.fma.f32(float %x, float bitcast (i32 ptrtoint (i32* @external to i32) to float), float %z)
+define float @fma_fneg_x_fneg_const(float %x, float %z) {
+  %x.fneg = fsub float -0.0, %x
+  %fma = call float @llvm.fma.f32(float %x.fneg, float fsub (float -0.0, float bitcast (i32 ptrtoint (i32* @external to i32) to float)), float %z)
+  ret float %fma
+}
+
+; CHECK-LABEL: @fma_fabs_x_fabs_y(
+; CHECK: %x.fabs = call float @llvm.fabs.f32(float %x)
+; CHECK: %y.fabs = call float @llvm.fabs.f32(float %y)
+; CHECK: %fma = call float @llvm.fma.f32(float %x.fabs, float %y.fabs, float %z)
+define float @fma_fabs_x_fabs_y(float %x, float %y, float %z) {
+  %x.fabs = call float @llvm.fabs.f32(float %x)
+  %y.fabs = call float @llvm.fabs.f32(float %y)
+  %fma = call float @llvm.fma.f32(float %x.fabs, float %y.fabs, float %z)
+  ret float %fma
+}
+
+; CHECK-LABEL: @fma_fabs_x_fabs_x(
+; CHECK: %fma = call float @llvm.fma.f32(float %x, float %x, float %z)
+define float @fma_fabs_x_fabs_x(float %x, float %z) {
+  %x.fabs = call float @llvm.fabs.f32(float %x)
+  %fma = call float @llvm.fma.f32(float %x.fabs, float %x.fabs, float %z)
+  ret float %fma
+}
+
+; CHECK-LABEL: @fma_fabs_x_fabs_x_fast(
+; CHECK: %fma = call fast float @llvm.fma.f32(float %x, float %x, float %z)
+define float @fma_fabs_x_fabs_x_fast(float %x, float %z) {
+  %x.fabs = call float @llvm.fabs.f32(float %x)
+  %fma = call fast float @llvm.fma.f32(float %x.fabs, float %x.fabs, float %z)
+  ret float %fma
+}
+
+; CHECK-LABEL: @fmuladd_fneg_x_fneg_y(
+; CHECK: %fmuladd = call float @llvm.fmuladd.f32(float %x, float %y, float %z)
+define float @fmuladd_fneg_x_fneg_y(float %x, float %y, float %z) {
+  %x.fneg = fsub float -0.0, %x
+  %y.fneg = fsub float -0.0, %y
+  %fmuladd = call float @llvm.fmuladd.f32(float %x.fneg, float %y.fneg, float %z)
+  ret float %fmuladd
+}
+
+; CHECK-LABEL: @fmuladd_fneg_x_fneg_y_fast(
+; CHECK: %fmuladd = call fast float @llvm.fmuladd.f32(float %x, float %y, float %z)
+define float @fmuladd_fneg_x_fneg_y_fast(float %x, float %y, float %z) {
+  %x.fneg = fsub float -0.0, %x
+  %y.fneg = fsub float -0.0, %y
+  %fmuladd = call fast float @llvm.fmuladd.f32(float %x.fneg, float %y.fneg, float %z)
+  ret float %fmuladd
+}
+
+; CHECK-LABEL: @fmuladd_fneg_const_fneg_y(
+; CHECK: %fmuladd = call float @llvm.fmuladd.f32(float bitcast (i32 ptrtoint (i32* @external to i32) to float), float %y, float %z)
+define float @fmuladd_fneg_const_fneg_y(float %y, float %z) {
+  %y.fneg = fsub float -0.0, %y
+  %fmuladd = call float @llvm.fmuladd.f32(float fsub (float -0.0, float bitcast (i32 ptrtoint (i32* @external to i32) to float)), float %y.fneg, float %z)
+  ret float %fmuladd
+}
+
+; CHECK-LABEL: @fmuladd_fneg_x_fneg_const(
+; CHECK: %fmuladd = call float @llvm.fmuladd.f32(float %x, float bitcast (i32 ptrtoint (i32* @external to i32) to float), float %z)
+define float @fmuladd_fneg_x_fneg_const(float %x, float %z) {
+  %x.fneg = fsub float -0.0, %x
+  %fmuladd = call float @llvm.fmuladd.f32(float %x.fneg, float fsub (float -0.0, float bitcast (i32 ptrtoint (i32* @external to i32) to float)), float %z)
+  ret float %fmuladd
+}
+
+; CHECK-LABEL: @fmuladd_fabs_x_fabs_y(
+; CHECK: %x.fabs = call float @llvm.fabs.f32(float %x)
+; CHECK: %y.fabs = call float @llvm.fabs.f32(float %y)
+; CHECK: %fmuladd = call float @llvm.fmuladd.f32(float %x.fabs, float %y.fabs, float %z)
+define float @fmuladd_fabs_x_fabs_y(float %x, float %y, float %z) {
+  %x.fabs = call float @llvm.fabs.f32(float %x)
+  %y.fabs = call float @llvm.fabs.f32(float %y)
+  %fmuladd = call float @llvm.fmuladd.f32(float %x.fabs, float %y.fabs, float %z)
+  ret float %fmuladd
+}
+
+; CHECK-LABEL: @fmuladd_fabs_x_fabs_x(
+; CHECK: %fmuladd = call float @llvm.fmuladd.f32(float %x, float %x, float %z)
+define float @fmuladd_fabs_x_fabs_x(float %x, float %z) {
+  %x.fabs = call float @llvm.fabs.f32(float %x)
+  %fmuladd = call float @llvm.fmuladd.f32(float %x.fabs, float %x.fabs, float %z)
+  ret float %fmuladd
+}
+
+; CHECK-LABEL: @fmuladd_fabs_x_fabs_x_fast(
+; CHECK: %fmuladd = call fast float @llvm.fmuladd.f32(float %x, float %x, float %z)
+define float @fmuladd_fabs_x_fabs_x_fast(float %x, float %z) {
+  %x.fabs = call float @llvm.fabs.f32(float %x)
+  %fmuladd = call fast float @llvm.fmuladd.f32(float %x.fabs, float %x.fabs, float %z)
+  ret float %fmuladd
+}
+
+attributes #0 = { nounwind }
+attributes #1 = { nounwind readnone }