[AArch64] Add new subtarget feature to fuse AES crypto operations

This feature enables the fusion of such operations on Cortex A57, as
recommended in its Software Optimisation Guide, section 4.13, and on Exynos
M1.

Differential revision: https://reviews.llvm.org/D28491

llvm-svn: 293738

1 files changed, 13 insertions, 0 deletions

diff --git a/llvm/lib/Target/AArch64/AArch64MacroFusion.cpp b/llvm/lib/Target/AArch64/AArch64MacroFusion.cpp
index c1adc862fed..f6d693262c3 100644
--- a/llvm/lib/Target/AArch64/AArch64MacroFusion.cpp
+++ b/llvm/lib/Target/AArch64/AArch64MacroFusion.cpp
@@ -116,6 +116,19 @@ static bool shouldScheduleAdjacent(const AArch64InstrInfo &TII,
         return true;
       }
 
+  if (ST.hasFuseAES())
+    // Fuse AES crypto operations.
+    switch(FirstOpcode) {
+    // AES encode.
+    case AArch64::AESErr:
+      return SecondOpcode == AArch64::AESMCrr ||
+             SecondOpcode == AArch64::INSTRUCTION_LIST_END;
+    // AES decode.
+    case AArch64::AESDrr:
+      return SecondOpcode == AArch64::AESIMCrr ||
+             SecondOpcode == AArch64::INSTRUCTION_LIST_END;
+    }
+
   return false;
 }