Fix sinc related bugs (rust-lang#814)

Author: wsmoses

enzyme/Enzyme/EnzymeLogic.cpp

@@ -2801,8 +2801,9 @@ void createTerminator(DiffeGradientUtils *gutils, BasicBlock *oBB,
       toret =
           nBuilder.CreateInsertValue(toret, gutils->diffe(ret, nBuilder), 1);
     } else {
-      toret = nBuilder.CreateInsertValue(
-          toret, Constant::getNullValue(ret->getType()), 1);
+      Type *retTy = gutils->getShadowType(ret->getType());
+      toret =
+          nBuilder.CreateInsertValue(toret, Constant::getNullValue(retTy), 1);
     }
     break;
   }

enzyme/Enzyme/InstructionDerivatives.td

@@ -142,3 +142,7 @@ def : CallPattern<(Op $x),
                   ["expm1"],
                   [(FMul (Intrinsic<"exp", [(TypeOf<""> $x)]> $x), (DiffeRet<"">))]
                   >;
+
+def : CallPattern<(Op $x),
+                  ["sinc", "sincf", "sincl"],
+                  [(FMul (DiffeRet<"">), (FDiv (FSub (Intrinsic<"cos", [(TypeOf<""> $x)]> $x), (Call<(SameFunc), [ReadNone,NoUnwind]> $x)), $x))]>;

enzyme/Enzyme/TypeAnalysis/TypeAnalysis.cpp

@@ -73,6 +73,7 @@ llvm::cl::opt<bool> EnzymeStrictAliasing(
 }
 
 const std::map<std::string, llvm::Intrinsic::ID> LIBM_FUNCTIONS = {
+    {"sinc", Intrinsic::not_intrinsic},
     {"cos", Intrinsic::cos},
     {"sin", Intrinsic::sin},
     {"tan", Intrinsic::not_intrinsic},

enzyme/test/Enzyme/ForwardModeVector/constret.ll

@@ -0,0 +1,32 @@
+; RUN: %opt < %s %loadEnzyme -enzyme -enzyme-preopt=false -mem2reg -simplifycfg -instsimplify -S | FileCheck %s
+
+%struct.Gradients = type { double, double }
+
+define double @f(double %x, i1 %c) {
+entry:
+  %v = select i1 %c, double 0.000000e+00, double 1.000000e+00
+  ret double %v
+}
+
+define double @tester(double %x, double %y) {
+entry:
+  %c = call double @f(double %x, i1 true)
+  %mul = fmul double %c, %y
+  ret double %mul
+}
+
+define %struct.Gradients @test_derivative(double %x, double %y){
+entry:
+  %call = call %struct.Gradients (double (double, double)*, ...) @__enzyme_fwddiff(double (double, double)* nonnull @tester, metadata !"enzyme_width", i64 2, double %x, double 1.000000e+00, double 0.000000e+00, double %y, double 0.000000e+00, double 1.000000e+00)
+  ret %struct.Gradients %call
+}
+
+declare %struct.Gradients @__enzyme_fwddiff(double (double, double)*, ...)
+
+; CHECK: define internal { double, [2 x double] } @fwddiffe2f(double %x, [2 x double] %"x'", i1 %c)
+; CHECK-NEXT: entry:
+; CHECK-NEXT:   %v = select i1 %c, double 0.000000e+00, double 1.000000e+00
+; CHECK-NEXT:   %0 = insertvalue { double, [2 x double] } undef, double %v, 0
+; CHECK-NEXT:   %1 = insertvalue { double, [2 x double] } %0, [2 x double] zeroinitializer, 1
+; CHECK-NEXT:   ret { double, [2 x double] } %1
+; CHECK-NEXT: }

enzyme/test/Enzyme/ReverseMode/sinc.ll

@@ -0,0 +1,31 @@
+; RUN: %opt < %s %loadEnzyme -enzyme -enzyme-preopt=false -mem2reg -instsimplify -simplifycfg -S | FileCheck %s
+
+; Function Attrs: nounwind readnone uwtable
+define double @tester(double %x) {
+entry:
+  %0 = tail call fast double @sinc(double %x)
+  ret double %0
+}
+
+define double @test_derivative(double %x) {
+entry:
+  %0 = tail call double (double (double)*, ...) @__enzyme_autodiff(double (double)* nonnull @tester, double %x)
+  ret double %0
+}
+
+; Function Attrs: nounwind readnone speculatable
+declare double @sinc(double)
+
+; Function Attrs: nounwind
+declare double @__enzyme_autodiff(double (double)*, ...)
+
+; CHECK: define internal { double } @diffetester(double %x, double %differeturn)
+; CHECK-NEXT: entry:
+; CHECK-NEXT:   %0 = call fast double @llvm.cos.f64(double %x)
+; CHECK-NEXT:   %1 = call fast double @sinc(double %x)
+; CHECK-NEXT:   %2 = fsub fast double %0, %1
+; CHECK-NEXT:   %3 = fdiv fast double %2, %x
+; CHECK-NEXT:   %4 = fmul fast double %differeturn, %3
+; CHECK-NEXT:   %5 = insertvalue { double } undef, double %4, 0
+; CHECK-NEXT:   ret { double } %5
+; CHECK-NEXT: }