Fixups

Author: MacDue

llvm/lib/Target/AArch64/AArch64Subtarget.h

@@ -181,9 +181,11 @@ class AArch64Subtarget final : public AArch64GenSubtargetInfo {
   /// the SME unit could result in a hazard. 0 = disabled.
   unsigned getStreamingHazardSize() const {
     // If StreamingHazardSize has been explicitly set to a value, use that.
-    // Otherwise, default to 1024 bytes when both SME and SVE are available,
-    // for all other configurations default to no streaming hazards.
-    return StreamingHazardSize.value_or(hasSME() && hasSVE() ? 1024 : 0);
+    // Otherwise, default to 1024 bytes when both SME and SVE are available
+    // (without FA64), for all other configurations default to no streaming
+    // hazards.
+    return StreamingHazardSize.value_or(
+        !hasSMEFA64() && hasSME() && hasSVE() ? 1024 : 0);
   }
 
   /// Returns true if the target has NEON and the function at runtime is known

llvm/test/CodeGen/AArch64/stack-hazard-defaults.ll

@@ -10,6 +10,9 @@
 ;; The hazard size can still be overridden/disabled when +sme,+sve is set.
 ; RUN: llc < %s -mtriple=aarch64 -mattr=+sme -mattr=+sve -aarch64-stack-hazard-size=0 | FileCheck %s --check-prefix=CHECK0
 
+;; When +sme-fa64 is set alongside +sme,+sve the default hazard size should be 0.
+; RUN: llc < %s -mtriple=aarch64 -mattr=+sme-fa64 -mattr=+sme -mattr=+sve | FileCheck %s --check-prefix=CHECK0
+
 ;; When +sme is set (without +sve) the default hazard size should be 0.
 ; RUN: llc < %s -mtriple=aarch64 -mattr=+sme | FileCheck %s --check-prefix=CHECK0