Handle dupnoneed in forward mode (rust-lang#396)

* Handle dupnoneed in forward mode

* Fix allocs with more than one parameter (rust-lang#397)

* Add test

Author: tgymnich

enzyme/Enzyme/AdjointGenerator.h

@@ -7455,7 +7455,11 @@ class AdjointGenerator
           IRBuilder<> Builder2(&call);
           getForwardBuilder(Builder2);
 
-          SmallVector<Value *, 2> args = {orig->getArgOperand(0)};
+          SmallVector<Value *, 2> args;
+          for (unsigned i = 0; i < orig->getNumArgOperands(); ++i) {
+            auto arg = orig->getArgOperand(i);
+            args.push_back(gutils->getNewFromOriginal(arg));
+          }
           CallInst *CI = Builder2.CreateCall(orig->getFunctionType(),
                                              orig->getCalledFunction(), args);
           CI->setAttributes(orig->getAttributes());

enzyme/Enzyme/EnzymeLogic.cpp

@@ -3848,7 +3848,9 @@ Function *EnzymeLogic::CreateForwardDiff(
 
   for (size_t i = 0; i < constant_args.size(); ++i) {
     auto arg = constant_args[i];
-    if (arg == DIFFE_TYPE::DUP_ARG) {
+    switch (arg) {
+    case DIFFE_TYPE::DUP_ARG:
+    case DIFFE_TYPE::DUP_NONEED: {
       newArgs += 1;
       auto pri = gutils->oldFunc->arg_begin() + i;
       auto dif = newArgs;
@@ -3857,6 +3859,12 @@ Function *EnzymeLogic::CreateForwardDiff(
       IRBuilder<> Builder(&BB.front());
 
       gutils->setDiffe(pri, dif, Builder);
+      break;
+    }
+    case DIFFE_TYPE::CONSTANT:
+      break;
+    case DIFFE_TYPE::OUT_DIFF:
+      report_fatal_error("unsupported DIFFE_TYPE");
     }
     newArgs += 1;
   }

enzyme/test/Enzyme/ForwardMode/calloc.ll

@@ -0,0 +1,40 @@
+; RUN: %opt < %s %loadEnzyme -enzyme -enzyme-preopt=false -mem2reg -instsimplify -adce -simplifycfg -S | FileCheck %s
+
+
+@enzyme_dupnoneed = dso_local global i32 0, align 4
+
+define dso_local double @f(double %x, i64 %arg) {
+entry:
+  %call = call noalias i8* @calloc(i64 8, i64 %arg)
+  %0 = bitcast i8* %call to double*
+  store double %x, double* %0, align 8
+  %1 = load double, double* %0, align 8
+  ret double %1
+}
+
+declare dso_local noalias i8* @calloc(i64, i64)
+
+define dso_local double @df(double %x) {
+entry:
+  %x.addr = alloca double, align 8
+  store double %x, double* %x.addr, align 8
+  %0 = load i32, i32* @enzyme_dupnoneed, align 4
+  %1 = load double, double* %x.addr, align 8
+  %call = call double (i8*, ...) @__enzyme_fwddiff(i8* bitcast (double (double,i64)* @f to i8*), i32 %0, double %1, double 1.000000e+00, i64 1)
+  ret double %call
+}
+
+declare dso_local double @__enzyme_fwddiff(i8*, ...)
+
+
+; CHECK: define internal double @fwddiffef(double %x, double %"x'", i64 %arg)
+; CHECK-NEXT: entry:
+; CHECK-NEXT:   %call = call noalias i8* @calloc(i64 8, i64 %arg)
+; CHECK-NEXT:   %0 = call noalias i8* @calloc(i64 8, i64 %arg)
+; CHECK-NEXT:   %"'ipc" = bitcast i8* %0 to double*
+; CHECK-NEXT:   %1 = bitcast i8* %call to double*
+; CHECK-NEXT:   store double %x, double* %1, align 8
+; CHECK-NEXT:   store double %"x'", double* %"'ipc", align 8
+; CHECK-NEXT:   %2 = load double, double* %"'ipc", align 8
+; CHECK-NEXT:   ret double %2
+; CHECK-NEXT: }