Add fmod (rust-lang#976)

Co-authored-by: Valentin Churavy <[email protected]>

Author: wsmoses

enzyme/Enzyme/InstructionDerivatives.td

@@ -171,3 +171,11 @@ def : CallPattern<(Op $x),
                   [
                   (FMul (DiffeRet<"">), (FMul (ConstantFP<"2.0"> $x), (FSub (FMul $x, (Call<(SameFunc), [ReadNone,NoUnwind]> $x)), (ConstantFP<"0.56418958354775628694807945156077258584405062932900"> $x) )))
                   ]>;
+
+def : CallPattern<(Op $x, $y),
+                  ["fmod", "fmodf", "fmodl"],
+                  [
+                  (DiffeRet<"">),
+                  (FMul (DiffeRet<"">), (FNeg (Intrinsic<"copysign", [(TypeOf<""> $x)]> (Intrinsic<"floor", [(TypeOf<""> $x)]> (Intrinsic<"fabs", [(TypeOf<""> $x)]> (FDiv $x, $y))), (FDiv $x, $y))))
+                  ]
+                  >;

enzyme/Enzyme/TypeAnalysis/TypeAnalysis.cpp

@@ -171,6 +171,7 @@ const std::map<std::string, llvm::Intrinsic::ID> LIBM_FUNCTIONS = {
     {"powi", Intrinsic::powi},
     {"cabs", Intrinsic::not_intrinsic},
     {"ldexp", Intrinsic::not_intrinsic},
+    {"fmod", Intrinsic::not_intrinsic},
 #if LLVM_VERSION_MAJOR >= 9
     {"lround", Intrinsic::lround},
     {"llround", Intrinsic::llround},

enzyme/test/Enzyme/ForwardMode/fmod.ll

@@ -0,0 +1,32 @@
+; RUN: %opt < %s %loadEnzyme -enzyme -early-cse -enzyme-preopt=false -S | FileCheck %s
+; RUN: if [ %llvmver -ge 12 ]; then %opt < %s %newLoadEnzyme -passes="enzyme,early-cse" -enzyme-preopt=false -S | FileCheck %s ; fi
+
+declare double @fmod(double, double)
+
+define double @tester(double %x, double %y) {
+entry:
+  %0 = call double @fmod(double %x, double %y)
+  ret double %0
+}
+
+define double @test_derivative(double %x, double %y) {
+entry:
+  %0 = tail call double (double (double, double)*, ...) @__enzyme_fwddiff(double (double, double)* nonnull @tester, double %x, double 1.0, double %y, double 1.0)
+  ret double %0
+}
+
+; Function Attrs: nounwind
+declare double @__enzyme_fwddiff(double (double, double)*, ...)
+
+
+; CHECK: define internal double @fwddiffetester(double %x, double %"x'", double %y, double %"y'") 
+; CHECK-NEXT: entry:
+; CHECK-NEXT:   %[[i0:.+]] = fdiv fast double %x, %y
+; CHECK-NEXT:   %[[i1:.+]] = call fast double @llvm.fabs.f64(double %[[i0]])
+; CHECK-NEXT:   %[[i2:.+]] = call fast double @llvm.floor.f64(double %[[i1]])
+; CHECK-NEXT:   %[[i3:.+]] = call fast double @llvm.copysign.f64(double %[[i2]], double %[[i0]])
+; CHECK-NEXT:   %[[i4:.+]] = {{(fsub fast double \-?0.000000e\+00,|fneg fast double)}} %[[i3]]
+; CHECK-NEXT:   %[[i5:.+]] = fmul fast double %"y'", %[[i4]]
+; CHECK-NEXT:   %[[i6:.+]] = fadd fast double %"x'", %[[i5]]
+; CHECK-NEXT:   ret double %[[i6]]
+; CHECK-NEXT: }

enzyme/test/Enzyme/ForwardMode/fmod2.ll

@@ -0,0 +1,25 @@
+; RUN: %opt < %s %loadEnzyme -enzyme -enzyme-preopt=false -S | FileCheck %s
+; RUN: %opt < %s %newLoadEnzyme -passes="enzyme" -enzyme-preopt=false -S | FileCheck %s
+
+declare double @fmod(double, double)
+
+define double @tester(double %x, double %y) {
+entry:
+  %0 = call double @fmod(double %x, double 1.000000e+00)
+  ret double %0
+}
+
+define double @test_derivative(double %x, double %y) {
+entry:
+  %0 = tail call double (double (double, double)*, ...) @__enzyme_fwddiff(double (double, double)* nonnull @tester, double %x, double 1.0, double %y, double 1.0)
+  ret double %0
+}
+
+; Function Attrs: nounwind
+declare double @__enzyme_fwddiff(double (double, double)*, ...)
+
+
+; CHECK: define internal double @fwddiffetester(double %x, double %"x'", double %y, double %"y'") 
+; CHECK-NEXT: entry:
+; CHECK-NEXT:   ret double %"x'"
+; CHECK-NEXT: }

enzyme/test/Enzyme/ReverseMode/fmod.ll

@@ -0,0 +1,32 @@
+; RUN: %opt < %s %loadEnzyme -enzyme -enzyme-preopt=false -mem2reg -early-cse -instsimplify -simplifycfg -S | FileCheck %s
+
+declare double @fmod(double, double)
+
+; Function Attrs: noinline nounwind readnone uwtable
+define double @tester(double %x, double %y) {
+entry:
+  %0 = call double @fmod(double %x, double %y)
+  ret double %0
+}
+
+define double @test_derivative(double %x, double %y) {
+entry:
+  %0 = tail call double (double (double, double)*, ...) @__enzyme_autodiff(double (double, double)* nonnull @tester, double %x, double %y)
+  ret double %0
+}
+
+; Function Attrs: nounwind
+declare double @__enzyme_autodiff(double (double, double)*, ...)
+
+; CHECK: define internal { double, double } @diffetester(double %x, double %y, double %differeturn) 
+; CHECK-NEXT: entry:
+; CHECK-NEXT:   %[[i0:.+]] = fdiv fast double %x, %y
+; CHECK-NEXT:   %[[i1:.+]] = call fast double @llvm.fabs.f64(double %[[i0]])
+; CHECK-NEXT:   %[[i2:.+]] = call fast double @llvm.floor.f64(double %[[i1]])
+; CHECK-NEXT:   %[[i3:.+]] = call fast double @llvm.copysign.f64(double %[[i2]], double %[[i0]])
+; CHECK-NEXT:   %[[i4:.+]] = {{(fsub fast double \-?0.000000e\+00,|fneg fast double)}} %[[i3]]
+; CHECK-NEXT:   %[[i5:.+]] = fmul fast double %differeturn, %[[i4]]
+; CHECK-NEXT:   %[[i6:.+]] = insertvalue { double, double } undef, double %differeturn, 0
+; CHECK-NEXT:   %[[i7:.+]] = insertvalue { double, double } %[[i6]], double %[[i5]], 1
+; CHECK-NEXT:   ret { double, double } %[[i7]]
+; CHECK-NEXT: }