[llvm] [TableGen] Use size returned by encodeULEB128 to simplify some code. NFC (PR #133750)

[Craig Topper via llvm-commits]

https://github.com/topperc created https://github.com/llvm/llvm-project/pull/133750

We can use the length to insert all the bytes at once instead of partially decoding them to insert one byte at a time.

>From 78149c505ac61cda0a3c691c662f38a9056b75d6 Mon Sep 17 00:00:00 2001
From: Craig Topper <craig.topper at sifive.com>
Date: Mon, 31 Mar 2025 09:38:48 -0700
Subject: [PATCH] [TableGen] Use size returned by encodeULEB128 to simplify
 some code. NFC

We can use the length to insert all the bytes at once instead of
partially decoding them to insert one byte at a time.
---
 llvm/utils/TableGen/DecoderEmitter.cpp | 22 ++++++++--------------
 1 file changed, 8 insertions(+), 14 deletions(-)

diff --git a/llvm/utils/TableGen/DecoderEmitter.cpp b/llvm/utils/TableGen/DecoderEmitter.cpp
index cf7c02db8842e..ecf9c84f86a6d 100644
--- a/llvm/utils/TableGen/DecoderEmitter.cpp
+++ b/llvm/utils/TableGen/DecoderEmitter.cpp
@@ -1430,16 +1430,12 @@ void FilterChooser::emitSingletonTableEntry(DecoderTableInfo &TableInfo,
     unsigned NumBits = Islands[I - 1].NumBits;
     assert(isUInt<8>(NumBits) && "NumBits overflowed uint8 table entry!");
     TableInfo.Table.push_back(MCD::OPC_CheckField);
-    uint8_t Buffer[16], *P;
-    encodeULEB128(Islands[I - 1].StartBit, Buffer);
-    for (P = Buffer; *P >= 128; ++P)
-      TableInfo.Table.push_back(*P);
-    TableInfo.Table.push_back(*P);
+    uint8_t Buffer[16];
+    unsigned Len = encodeULEB128(Islands[I - 1].StartBit, Buffer);
+    TableInfo.Table.insert(TableInfo.Table.end(), Buffer, Buffer + Len);
     TableInfo.Table.push_back(NumBits);
-    encodeULEB128(Islands[I - 1].FieldVal, Buffer);
-    for (P = Buffer; *P >= 128; ++P)
-      TableInfo.Table.push_back(*P);
-    TableInfo.Table.push_back(*P);
+    Len = encodeULEB128(Islands[I - 1].FieldVal, Buffer);
+    TableInfo.Table.insert(TableInfo.Table.end(), Buffer, Buffer + Len);
     // Push location for NumToSkip backpatching.
     TableInfo.FixupStack.back().push_back(TableInfo.Table.size());
     // The fixup is always 24-bits, so go ahead and allocate the space
@@ -1469,11 +1465,9 @@ void FilterChooser::emitSingletonTableEntry(DecoderTableInfo &TableInfo,
   TableInfo.Table.push_back(HasCompleteDecoder ? MCD::OPC_Decode
                                                : MCD::OPC_TryDecode);
   NumEncodingsSupported++;
-  uint8_t Buffer[16], *p;
-  encodeULEB128(Opc.Opcode, Buffer);
-  for (p = Buffer; *p >= 128; ++p)
-    TableInfo.Table.push_back(*p);
-  TableInfo.Table.push_back(*p);
+  uint8_t Buffer[16];
+  unsigned Len = encodeULEB128(Opc.Opcode, Buffer);
+  TableInfo.Table.insert(TableInfo.Table.end(), Buffer, Buffer + Len);
 
   SmallString<16> Bytes;
   raw_svector_ostream S(Bytes);