From 8e36e65e6570827796acf3ae7df421fc244ca8aa Mon Sep 17 00:00:00 2001
From: William Moses <gh@wsmoses.com>
Date: Wed, 1 Jan 2025 14:18:42 -0500
Subject: [PATCH] Improve cast ft error (#2213)

---
 enzyme/Enzyme/AdjointGenerator.h | 46 +++++++++++++++++---------------
 1 file changed, 24 insertions(+), 22 deletions(-)

diff --git a/enzyme/Enzyme/AdjointGenerator.h b/enzyme/Enzyme/AdjointGenerator.h
index 96b8494302e..655bdca6943 100644
--- a/enzyme/Enzyme/AdjointGenerator.h
+++ b/enzyme/Enzyme/AdjointGenerator.h
@@ -1380,31 +1380,33 @@ class AdjointGenerator : public llvm::InstVisitor<AdjointGenerator> {
           ss << "Cannot deduce adding type (cast) of " << I;
           EmitNoTypeError(str, I, gutils, Builder2);
         }
-        assert(FT);
 
-        auto rule = [&](Value *dif) {
-          if (I.getOpcode() == CastInst::CastOps::FPTrunc ||
-              I.getOpcode() == CastInst::CastOps::FPExt) {
-            return Builder2.CreateFPCast(dif, op0->getType());
-          } else if (I.getOpcode() == CastInst::CastOps::BitCast) {
-            return Builder2.CreateBitCast(dif, op0->getType());
-          } else if (I.getOpcode() == CastInst::CastOps::Trunc) {
-            // TODO CHECK THIS
-            return Builder2.CreateZExt(dif, op0->getType());
-          } else {
-            std::string s;
-            llvm::raw_string_ostream ss(s);
-            ss << *I.getParent()->getParent() << "\n";
-            ss << "cannot handle above cast " << I << "\n";
-            EmitNoDerivativeError(ss.str(), I, gutils, Builder2);
-            return (llvm::Value *)UndefValue::get(op0->getType());
-          }
-        };
+        if (FT) {
+
+          auto rule = [&](Value *dif) {
+            if (I.getOpcode() == CastInst::CastOps::FPTrunc ||
+                I.getOpcode() == CastInst::CastOps::FPExt) {
+              return Builder2.CreateFPCast(dif, op0->getType());
+            } else if (I.getOpcode() == CastInst::CastOps::BitCast) {
+              return Builder2.CreateBitCast(dif, op0->getType());
+            } else if (I.getOpcode() == CastInst::CastOps::Trunc) {
+              // TODO CHECK THIS
+              return Builder2.CreateZExt(dif, op0->getType());
+            } else {
+              std::string s;
+              llvm::raw_string_ostream ss(s);
+              ss << *I.getParent()->getParent() << "\n";
+              ss << "cannot handle above cast " << I << "\n";
+              EmitNoDerivativeError(ss.str(), I, gutils, Builder2);
+              return (llvm::Value *)UndefValue::get(op0->getType());
+            }
+          };
 
-        Value *dif = diffe(&I, Builder2);
-        Value *diff = applyChainRule(op0->getType(), Builder2, rule, dif);
+          Value *dif = diffe(&I, Builder2);
+          Value *diff = applyChainRule(op0->getType(), Builder2, rule, dif);
 
-        addToDiffe(orig_op0, diff, Builder2, FT);
+          addToDiffe(orig_op0, diff, Builder2, FT);
+        }
       }
 
       Type *diffTy = gutils->getShadowType(I.getType());