[clang] [clang] fix half && bfloat16 convert node expr codegen (PR #89051)

[via cfe-commits]

https://github.com/JinjinLi868 created https://github.com/llvm/llvm-project/pull/89051

Data type conversion between fp16 and bf16 will generate fptrunc and fpextend nodes, but they are actually bitcast nodes.


>From 02c11a9db49dd34839feb8329cfb8dbe4bc45763 Mon Sep 17 00:00:00 2001
From: Jinjin Li <lijinjin.868 at bytedance.com>
Date: Wed, 17 Apr 2024 16:44:50 +0800
Subject: [PATCH] [clang] fix half && bfloat16 convert node expr codegen

Data type conversion between fp16 and bf16 will generate fptrunc and fpextend nodes, but they are actually bitcast nodes.
---
 clang/lib/CodeGen/CGExprScalar.cpp | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/clang/lib/CodeGen/CGExprScalar.cpp b/clang/lib/CodeGen/CGExprScalar.cpp
index 1f18e0d5ba409a..da5a410f040d1b 100644
--- a/clang/lib/CodeGen/CGExprScalar.cpp
+++ b/clang/lib/CodeGen/CGExprScalar.cpp
@@ -1431,9 +1431,12 @@ Value *ScalarExprEmitter::EmitScalarCast(Value *Src, QualType SrcType,
     return Builder.CreateFPToUI(Src, DstTy, "conv");
   }
 
-  if (DstElementTy->getTypeID() < SrcElementTy->getTypeID())
+  if ((DstElementTy->is16bitFPTy() && SrcElementTy->is16bitFPTy()))
+    return Builder.CreateBitCast(Src, DstTy, "conv");
+  else if (DstElementTy->getTypeID() < SrcElementTy->getTypeID())
     return Builder.CreateFPTrunc(Src, DstTy, "conv");
-  return Builder.CreateFPExt(Src, DstTy, "conv");
+  else
+    return Builder.CreateFPExt(Src, DstTy, "conv");
 }
 
 /// Emit a conversion from the specified type to the specified destination type,
@@ -1906,7 +1909,9 @@ Value *ScalarExprEmitter::VisitConvertVectorExpr(ConvertVectorExpr *E) {
   } else {
     assert(SrcEltTy->isFloatingPointTy() && DstEltTy->isFloatingPointTy() &&
            "Unknown real conversion");
-    if (DstEltTy->getTypeID() < SrcEltTy->getTypeID())
+    if ((DstEltTy->is16bitFPTy() && SrcEltTy->is16bitFPTy()))
+      Res = Builder.CreateBitCast(Src, DstTy, "conv");
+    else if (DstEltTy->getTypeID() < SrcEltTy->getTypeID())
       Res = Builder.CreateFPTrunc(Src, DstTy, "conv");
     else
       Res = Builder.CreateFPExt(Src, DstTy, "conv");