aboutsummaryrefslogtreecommitdiff
path: root/llvm/lib/IR/Function.cpp
diff options
context:
space:
mode:
authorRahul Joshi <rjoshi@nvidia.com>2024-09-04 14:46:48 -0700
committerGitHub <noreply@github.com>2024-09-04 14:46:48 -0700
commitdcf0160bd61d150e7b94067fcd991b466a361b08 (patch)
treec4f1706420e268d68157e75f6a362a34928f97f3 /llvm/lib/IR/Function.cpp
parentdd754cd262222bcb489038ac791e4278d90697f0 (diff)
downloadllvm-dcf0160bd61d150e7b94067fcd991b466a361b08.zip
llvm-dcf0160bd61d150e7b94067fcd991b466a361b08.tar.gz
llvm-dcf0160bd61d150e7b94067fcd991b466a361b08.tar.bz2
[TableGen] Optimize intrinsic info type signature encoding (#106809)
Change the "fixed encoding" table used for encoding intrinsic type signature to use 16-bit encoding as opposed to 32-bit. This results in both space and time improvements. For space, the total static storage size (in bytes) of this info reduces by 50%: - Current = 14193*4 (Fixed table) + 16058 + 3 (Long Table) = 72833 - New size = 14193*2 (Fixed table) + 19879 + 3 (Long Table) = 48268. - Reduction = 50.9% For time, with the added benchmark, we see a 7.3% speedup in `GetIntrinsicInfoTableEntries` benchmark. Actual output of the benchmark in included in the GitHub MR.
Diffstat (limited to 'llvm/lib/IR/Function.cpp')
-rw-r--r--llvm/lib/IR/Function.cpp14
1 files changed, 8 insertions, 6 deletions
diff --git a/llvm/lib/IR/Function.cpp b/llvm/lib/IR/Function.cpp
index 69520fd..afef893 100644
--- a/llvm/lib/IR/Function.cpp
+++ b/llvm/lib/IR/Function.cpp
@@ -1381,22 +1381,24 @@ static void DecodeIITType(unsigned &NextElt, ArrayRef<unsigned char> Infos,
void Intrinsic::getIntrinsicInfoTableEntries(ID id,
SmallVectorImpl<IITDescriptor> &T){
+ static_assert(sizeof(IIT_Table[0]) == 2,
+ "Expect 16-bit entries in IIT_Table");
// Check to see if the intrinsic's type was expressible by the table.
- unsigned TableVal = IIT_Table[id-1];
+ uint16_t TableVal = IIT_Table[id - 1];
// Decode the TableVal into an array of IITValues.
- SmallVector<unsigned char, 8> IITValues;
+ SmallVector<unsigned char> IITValues;
ArrayRef<unsigned char> IITEntries;
unsigned NextElt = 0;
- if ((TableVal >> 31) != 0) {
+ if (TableVal >> 15) {
// This is an offset into the IIT_LongEncodingTable.
IITEntries = IIT_LongEncodingTable;
// Strip sentinel bit.
- NextElt = (TableVal << 1) >> 1;
+ NextElt = TableVal & 0x7fff;
} else {
- // Decode the TableVal into an array of IITValues. If the entry was encoded
- // into a single word in the table itself, decode it now.
+ // If the entry was encoded into a single word in the table itself, decode
+ // it from an array of nibbles to an array of bytes.
do {
IITValues.push_back(TableVal & 0xF);
TableVal >>= 4;