[llvm] 54b5b78 - [CodeGen] Use natural type for StackMaps::ConstPool. NFC. (#208732)

[via llvm-commits]

Author: Jay Foad
Date: 2026-07-10T17:12:42+01:00
New Revision: 54b5b78a6332a0faa13f2297a5b3751a1d7544a9

URL: https://github.com/llvm/llvm-project/commit/54b5b78a6332a0faa13f2297a5b3751a1d7544a9
DIFF: https://github.com/llvm/llvm-project/commit/54b5b78a6332a0faa13f2297a5b3751a1d7544a9.diff

LOG: [CodeGen] Use natural type for StackMaps::ConstPool. NFC. (#208732)

This is mostly just a revert of e839965faa22 which switched to using
unsigned types to work around problems with DenseMap sentinel values.
Since DenseMaps no longer have sentinels we can use signed types to
match the values that are stored in the map.

Added: 
    

Modified: 
    llvm/include/llvm/CodeGen/StackMaps.h
    llvm/lib/CodeGen/StackMaps.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/include/llvm/CodeGen/StackMaps.h b/llvm/include/llvm/CodeGen/StackMaps.h
index 9ef8fffec1387..cdb0a6c80188d 100644
--- a/llvm/include/llvm/CodeGen/StackMaps.h
+++ b/llvm/include/llvm/CodeGen/StackMaps.h
@@ -308,7 +308,7 @@ class StackMaps {
 
   using LocationVec = SmallVector<Location, 8>;
   using LiveOutVec = SmallVector<LiveOutReg, 8>;
-  using ConstantPool = MapVector<uint64_t, uint64_t>;
+  using ConstantPool = MapVector<int64_t, int64_t>;
 
   struct FunctionInfo {
     uint64_t StackSize = 0;

diff  --git a/llvm/lib/CodeGen/StackMaps.cpp b/llvm/lib/CodeGen/StackMaps.cpp
index 4e95f883ce31b..bd21e0c34fd97 100644
--- a/llvm/lib/CodeGen/StackMaps.cpp
+++ b/llvm/lib/CodeGen/StackMaps.cpp
@@ -240,11 +240,6 @@ StackMaps::parseOperand(MachineInstr::const_mop_iterator MOI,
       if (isInt<32>(Imm)) {
         Locs.emplace_back(Location::Constant, sizeof(int64_t), 0, Imm);
       } else {
-        // ConstPool is intentionally a MapVector of 'uint64_t's (as
-        // opposed to 'int64_t's).  We should never be in a situation
-        // where we have to insert the empty key into a map, and for a
-        // DenseMap<uint64_t, T> this is (uint64_t)-1.  It can be and is
-        // represented using 32 bit integers.
         auto Result = ConstPool.insert(std::make_pair(Imm, Imm));
         Locs.emplace_back(Location::ConstantIndex, sizeof(int64_t), 0,
                           Result.first - ConstPool.begin());