[AVX] Make Inits Foldable

Manage Inits in a FoldingSet.  This provides several benefits:

- Memory for Inits is properly managed

- Duplicate Inits are folded into Flyweights, saving memory

- It enforces const-correctness, protecting against certain classes
  of bugs

The above benefits allow Inits to be used in more contexts, which in
turn provides more dynamism to TableGen.  This enhanced capability
will be used by the AVX code generator to a fold common patterns
together.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@134907 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 3 insertions, 3 deletions

diff --git a/utils/TableGen/X86RecognizableInstr.cpp b/utils/TableGen/X86RecognizableInstr.cpp
index f7518a988c..f7170c41e7 100644
--- a/utils/TableGen/X86RecognizableInstr.cpp
+++ b/utils/TableGen/X86RecognizableInstr.cpp
@@ -162,7 +162,7 @@ static bool isRegFormat(uint8_t form) {
 /// @param init - A reference to the BitsInit to be decoded.
 /// @return     - The field, with the first bit in the BitsInit as the lowest
 ///               order bit.
-static uint8_t byteFromBitsInit(BitsInit &init) {
+static uint8_t byteFromBitsInit(const BitsInit &init) {
   int width = init.getNumBits();
 
   assert(width <= 8 && "Field is too large for uint8_t!");
@@ -173,7 +173,7 @@ static uint8_t byteFromBitsInit(BitsInit &init) {
   uint8_t ret = 0;
 
   for (index = 0; index < width; index++) {
-    if (static_cast<BitInit*>(init.getBit(index))->getValue())
+    if (static_cast<const BitInit*>(init.getBit(index))->getValue())
       ret |= mask;
 
     mask <<= 1;
@@ -189,7 +189,7 @@ static uint8_t byteFromBitsInit(BitsInit &init) {
 /// @param name - The name of the field in the record.
 /// @return     - The field, as translated by byteFromBitsInit().
 static uint8_t byteFromRec(const Record* rec, const std::string &name) {
-  BitsInit* bits = rec->getValueAsBitsInit(name);
+  const BitsInit* bits = rec->getValueAsBitsInit(name);
   return byteFromBitsInit(*bits);
 }