[clang] [Clang][RISCV] bfloat uses 'y' instead of 'b' (PR #76575)

[Michael Maitland via cfe-commits]

https://github.com/michaelmaitland created https://github.com/llvm/llvm-project/pull/76575

Builtins.def says that bfloat should be represented by the 'y' character, not the 'b' character. The 'b' character is specified to use 'b'. The implementation currently uses 'b' correctly for boolean and incorrectly re-uses 'b' for bfloat.

This was not caught since no builtins are emitted in build/tools/clang/include/clang/Basic/riscv_sifive_vector_builtins.inc. Don't know that we can test this without creating builtins that expose this issue, although I'm not sure we really want to do that.

>From 913ad0a5fc48429cdcd09bdbff88023427813760 Mon Sep 17 00:00:00 2001
From: Michael Maitland <michaeltmaitland at gmail.com>
Date: Fri, 29 Dec 2023 10:11:34 -0800
Subject: [PATCH] [Clang][RISCV] bfloat uses 'y' instead of 'b'

Builtins.def says that bfloat should be represented by the 'y'
character, not the 'b' character. The 'b' character is specified to use
'b'. The implementation currently uses 'b' correctly for boolean and incorrectly
re-uses 'b' for bfloat.

This was not caught since no builtins are emitted in
build/tools/clang/include/clang/Basic/riscv_sifive_vector_builtins.inc.
Don't know that we can test this without creating builtins that expose
this issue, although I'm not sure we really want to do that.
---
 clang/include/clang/Basic/riscv_sifive_vector.td | 2 +-
 clang/include/clang/Basic/riscv_vector_common.td | 2 +-
 clang/lib/Support/RISCVVIntrinsicUtils.cpp       | 2 +-
 clang/utils/TableGen/RISCVVEmitter.cpp           | 2 +-
 4 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/clang/include/clang/Basic/riscv_sifive_vector.td b/clang/include/clang/Basic/riscv_sifive_vector.td
index e19a34f7632fdc..0d471f6c554c22 100644
--- a/clang/include/clang/Basic/riscv_sifive_vector.td
+++ b/clang/include/clang/Basic/riscv_sifive_vector.td
@@ -109,7 +109,7 @@ multiclass RVVVFWMACCBuiltinSet<list<list<string>> suffixes_prototypes> {
       Name = NAME,
       HasMasked = false,
       Log2LMUL = [-2, -1, 0, 1, 2] in
-    defm NAME : RVVOutOp1Op2BuiltinSet<NAME, "b", suffixes_prototypes>;
+    defm NAME : RVVOutOp1Op2BuiltinSet<NAME, "y", suffixes_prototypes>;
 }
 
 multiclass RVVVQMACCDODBuiltinSet<list<list<string>> suffixes_prototypes> {
diff --git a/clang/include/clang/Basic/riscv_vector_common.td b/clang/include/clang/Basic/riscv_vector_common.td
index 4036ce8e6903f4..040db6f0cdbfb0 100644
--- a/clang/include/clang/Basic/riscv_vector_common.td
+++ b/clang/include/clang/Basic/riscv_vector_common.td
@@ -41,7 +41,7 @@
 //   x: float16_t (half)
 //   f: float32_t (float)
 //   d: float64_t (double)
-//   b: bfloat16_t (bfloat16)
+//   y: bfloat16_t (bfloat16)
 //
 // This way, given an LMUL, a record with a TypeRange "sil" will cause the
 // definition of 3 builtins. Each type "t" in the TypeRange (in this example
diff --git a/clang/lib/Support/RISCVVIntrinsicUtils.cpp b/clang/lib/Support/RISCVVIntrinsicUtils.cpp
index bf47461b59e0ad..2de977a3dc720b 100644
--- a/clang/lib/Support/RISCVVIntrinsicUtils.cpp
+++ b/clang/lib/Support/RISCVVIntrinsicUtils.cpp
@@ -203,7 +203,7 @@ void RVVType::initBuiltinStr() {
     }
     break;
   case ScalarTypeKind::BFloat:
-    BuiltinStr += "b";
+    BuiltinStr += "y";
     break;
   default:
     llvm_unreachable("ScalarType is invalid!");
diff --git a/clang/utils/TableGen/RISCVVEmitter.cpp b/clang/utils/TableGen/RISCVVEmitter.cpp
index da2a885ce8512f..d570bcae8d8636 100644
--- a/clang/utils/TableGen/RISCVVEmitter.cpp
+++ b/clang/utils/TableGen/RISCVVEmitter.cpp
@@ -151,7 +151,7 @@ static BasicType ParseBasicType(char c) {
   case 'd':
     return BasicType::Float64;
     break;
-  case 'b':
+  case 'y':
     return BasicType::BFloat16;
     break;
   default: