[TableGen] Avoid field lookup in a performance critical place (NFC)

[s-barannikov]

Target.getInstructions() is called by virtually all TableGen backends. It is slow, and one of the two factors is the use of an expensive predicate in llvm::sort. This change speeds up sorting by 10x.

[llvmbot]

@llvm/pr-subscribers-tablegen

Author: Sergei Barannikov (s-barannikov)

Changes

Target.getInstructions() is called by basically all TableGen backends. It is slow, and one of the two factors is the use of an expensive predicate in llvm::sort. This change speeds up sorting by 10x.

---

Full diff: https://github.com/llvm/llvm-project/pull/154871.diff

1 Files Affected:

• (modified) llvm/utils/TableGen/Common/CodeGenTarget.cpp (+2-2)

diff --git a/llvm/utils/TableGen/Common/CodeGenTarget.cpp b/llvm/utils/TableGen/Common/CodeGenTarget.cpp
index a9002c5860fa3..8982927eeefcf 100644
--- a/llvm/utils/TableGen/Common/CodeGenTarget.cpp
+++ b/llvm/utils/TableGen/Common/CodeGenTarget.cpp
@@ -270,8 +270,8 @@ void CodeGenTarget::ComputeInstrsByEnum() const {
         const Record &D2 = *Rec2->TheDef;
         // Sort all pseudo instructions before non-pseudo ones, and sort by name
         // within.
-        return std::tuple(!D1.getValueAsBit("isPseudo"), D1.getName()) <
-               std::tuple(!D2.getValueAsBit("isPseudo"), D2.getName());
+        return std::tuple(!Rec1->isPseudo, D1.getName()) <
+               std::tuple(!Rec2->isPseudo, D2.getName());
       });
 
   // Assign an enum value to each instruction according to the sorted order.

[jurahul]

nice find! LGTM