[llvm] 06e24fa - [AArch64][SME] Scan function attributes once in SMEAttrs (NFC) (#210924)

[via llvm-commits]

Author: Cullen Rhodes
Date: 2026-07-22T08:27:17+01:00
New Revision: 06e24fa50e58068c6c9dabde2d38a1cdfd34b50d

URL: https://github.com/llvm/llvm-project/commit/06e24fa50e58068c6c9dabde2d38a1cdfd34b50d
DIFF: https://github.com/llvm/llvm-project/commit/06e24fa50e58068c6c9dabde2d38a1cdfd34b50d.diff

LOG: [AArch64][SME] Scan function attributes once in SMEAttrs (NFC) (#210924)

Profiling sqlite on aarch64-O3 shows ~0.5% of compile-time is spent in
the SMEAttrs constructor, mostly from the inliner's areInlineCompatible
and getInlineCallPenalty hooks.

SMEAttrs does 14 string attribute lookups. Invert this to instead walk
the function attributes once and build the mask with a StringSwitch.

Improves CTMark geomean -0.20%, sqlite -0.40%.

https://llvm-compile-time-tracker.com/compare.php?from=4aa1590ad66a1bff9b3c74b4a2c7366473015b4c&to=37796f0f92101225e2fb5b6924acfdb5cba1b672&stat=instructions%3Au

Assisted-by: codex

Added: 
    

Modified: 
    llvm/lib/Target/AArch64/AArch64SMEAttributes.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/AArch64/AArch64SMEAttributes.cpp b/llvm/lib/Target/AArch64/AArch64SMEAttributes.cpp
index dd9f74df3609c..0a5d475c211a7 100644
--- a/llvm/lib/Target/AArch64/AArch64SMEAttributes.cpp
+++ b/llvm/lib/Target/AArch64/AArch64SMEAttributes.cpp
@@ -8,6 +8,7 @@
 
 #include "AArch64SMEAttributes.h"
 #include "AArch64ISelLowering.h"
+#include "llvm/ADT/StringSwitch.h"
 #include "llvm/IR/InstrTypes.h"
 #include "llvm/IR/RuntimeLibcalls.h"
 #include <cassert>
@@ -45,34 +46,31 @@ SMEAttrs::SMEAttrs(const AttributeList &Attrs) {
   // To avoid introducing any compatibility issues don't reuse
   // 'aarch64_zt0_undef' for another purpose.
   Bitmask = 0;
-  if (Attrs.hasFnAttr("aarch64_pstate_sm_enabled"))
-    Bitmask |= SM_Enabled;
-  if (Attrs.hasFnAttr("aarch64_pstate_sm_compatible"))
-    Bitmask |= SM_Compatible;
-  if (Attrs.hasFnAttr("aarch64_pstate_sm_body"))
-    Bitmask |= SM_Body;
-  if (Attrs.hasFnAttr("aarch64_za_state_agnostic"))
-    Bitmask |= ZA_State_Agnostic;
-  if (Attrs.hasFnAttr("aarch64_in_za"))
-    Bitmask |= encodeZAState(StateValue::In);
-  if (Attrs.hasFnAttr("aarch64_out_za"))
-    Bitmask |= encodeZAState(StateValue::Out);
-  if (Attrs.hasFnAttr("aarch64_inout_za"))
-    Bitmask |= encodeZAState(StateValue::InOut);
-  if (Attrs.hasFnAttr("aarch64_preserves_za"))
-    Bitmask |= encodeZAState(StateValue::Preserved);
-  if (Attrs.hasFnAttr("aarch64_new_za"))
-    Bitmask |= encodeZAState(StateValue::New);
-  if (Attrs.hasFnAttr("aarch64_in_zt0"))
-    Bitmask |= encodeZT0State(StateValue::In);
-  if (Attrs.hasFnAttr("aarch64_out_zt0"))
-    Bitmask |= encodeZT0State(StateValue::Out);
-  if (Attrs.hasFnAttr("aarch64_inout_zt0"))
-    Bitmask |= encodeZT0State(StateValue::InOut);
-  if (Attrs.hasFnAttr("aarch64_preserves_zt0"))
-    Bitmask |= encodeZT0State(StateValue::Preserved);
-  if (Attrs.hasFnAttr("aarch64_new_zt0"))
-    Bitmask |= encodeZT0State(StateValue::New);
+  for (Attribute Attr : Attrs.getFnAttrs()) {
+    if (!Attr.isStringAttribute())
+      continue;
+
+    StringRef Kind = Attr.getKindAsString();
+    if (!Kind.consume_front("aarch64_"))
+      continue;
+
+    Bitmask |= StringSwitch<unsigned>(Kind)
+                   .Case("pstate_sm_enabled", SM_Enabled)
+                   .Case("pstate_sm_compatible", SM_Compatible)
+                   .Case("pstate_sm_body", SM_Body)
+                   .Case("za_state_agnostic", ZA_State_Agnostic)
+                   .Case("in_za", encodeZAState(StateValue::In))
+                   .Case("out_za", encodeZAState(StateValue::Out))
+                   .Case("inout_za", encodeZAState(StateValue::InOut))
+                   .Case("preserves_za", encodeZAState(StateValue::Preserved))
+                   .Case("new_za", encodeZAState(StateValue::New))
+                   .Case("in_zt0", encodeZT0State(StateValue::In))
+                   .Case("out_zt0", encodeZT0State(StateValue::Out))
+                   .Case("inout_zt0", encodeZT0State(StateValue::InOut))
+                   .Case("preserves_zt0", encodeZT0State(StateValue::Preserved))
+                   .Case("new_zt0", encodeZT0State(StateValue::New))
+                   .Default(Normal);
+  }
 }
 
 void SMEAttrs::addKnownFunctionAttrs(StringRef FuncName,