[NFC][DebugInfo] Make MDNodeKeyImpl<DILocation>::Column 16 bits

[OCHyams]

Column is limited to 16 bits in several places in the compiler:

llvm-project/llvm/lib/IR/DebugInfoMetadata.cpp

Line 87 in a3c7d46

SubclassData16 = Column;

llvm-project/llvm/lib/AsmParser/LLParser.cpp

Line 4706 in a3c7d46

ColumnField() : MDUnsignedField(0, UINT16_MAX) {}

Slight compile time improvement due to reducing hash_combine workload in MDNodeKeyImpl<DILocation>::getHashValue().

https://llvm-compile-time-tracker.com/compare.php?from=2b7b0e178259a910355631d7d648c89052000872&to=89490929c34f45842df1588cf78d836f51c2c222&stat=instructions%3Au

(positively affects compile time regardless of whether Key Instructions is enabled)

[llvmbot]

@llvm/pr-subscribers-llvm-ir

@llvm/pr-subscribers-debuginfo

Author: Orlando Cazalet-Hyams (OCHyams)

Changes

Column is limited to 16 bits in several places in the compiler:

llvm-project/llvm/lib/IR/DebugInfoMetadata.cpp

Line 87 in a3c7d46

SubclassData16 = Column;

llvm-project/llvm/lib/AsmParser/LLParser.cpp

Line 4706 in a3c7d46

ColumnField() : MDUnsignedField(0, UINT16_MAX) {}

Slight compile time improvement due to reducing hash_combine workload in MDNodeKeyImpl<DILocation>::getHashValue().

https://llvm-compile-time-tracker.com/compare.php?from=2b7b0e178259a910355631d7d648c89052000872&amp;to=89490929c34f45842df1588cf78d836f51c2c222&amp;stat=instructions%3Au

(positively affects compile time regardless of whether Key Instructions is enabled)

---

Full diff: https://github.com/llvm/llvm-project/pull/143399.diff

1 Files Affected:

• (modified) llvm/lib/IR/LLVMContextImpl.h (+1-1)

diff --git a/llvm/lib/IR/LLVMContextImpl.h b/llvm/lib/IR/LLVMContextImpl.h
index 7b6083a7a3496..946dc3188aeb1 100644
--- a/llvm/lib/IR/LLVMContextImpl.h
+++ b/llvm/lib/IR/LLVMContextImpl.h
@@ -311,7 +311,7 @@ template <> struct MDNodeKeyImpl<MDTuple> : MDNodeOpsKey {
 /// DenseMapInfo for DILocation.
 template <> struct MDNodeKeyImpl<DILocation> {
   unsigned Line;
-  unsigned Column;
+  uint16_t Column;
   Metadata *Scope;
   Metadata *InlinedAt;
   bool ImplicitCode;

[nikic]

LGTM, though I wonder whether we should also change the ctor to accept uint16_t?