[PATCH] D67107: [ARM] Add patterns for bitreverse intrinsic on MVE

[oliver cruickshank via Phabricator via llvm-commits]

oliverlars created this revision.
oliverlars added reviewers: dmgreen, SjoerdMeijer, samparker, simon_tatham, t.p.northover.
Herald added subscribers: llvm-commits, hiraditya, kristof.beyls, javed.absar.
Herald added a project: LLVM.

BITREVERSE can use the VBRSR which will reverse and right shift. Shifting right by 0 will just reverse the bits.


Repository:
  rL LLVM

https://reviews.llvm.org/D67107

Files:
  llvm/lib/Target/ARM/ARMISelLowering.cpp
  llvm/lib/Target/ARM/ARMInstrMVE.td
  llvm/test/CodeGen/Thumb2/mve-bitreverse.ll


Index: llvm/test/CodeGen/Thumb2/mve-bitreverse.ll
===================================================================
--- /dev/null
+++ llvm/test/CodeGen/Thumb2/mve-bitreverse.ll
@@ -0,0 +1,37 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -mtriple=thumbv8.1m.main-arm-none-eabi -mattr=+mve %s -o - | FileCheck %s
+
+define arm_aapcs_vfpcc <4 x i32> @brv_4i32_t(<4 x i32> %src){
+; CHECK-LABEL: brv_4i32_t:
+; CHECK:       @ %bb.0: @ %entry
+; CHECK-NEXT:    vbrsr.32 q0, q0, #0
+; CHECK-NEXT:    bx lr
+entry:
+  %0 = call <4 x i32> @llvm.bitreverse.v4i32(<4 x i32> %src)
+  ret <4 x i32> %0
+}
+
+define arm_aapcs_vfpcc <8 x i16> @brv_8i16_t(<8 x i16> %src){
+; CHECK-LABEL: brv_8i16_t:
+; CHECK:       @ %bb.0: @ %entry
+; CHECK-NEXT:    vbrsr.16 q0, q0, #0
+; CHECK-NEXT:    bx lr
+entry:
+  %0 = call <8 x i16> @llvm.bitreverse.v8i16(<8 x i16> %src)
+  ret <8 x i16> %0
+}
+
+define arm_aapcs_vfpcc <16 x i8> @brv_16i8_t(<16 x i8> %src){
+; CHECK-LABEL: brv_16i8_t:
+; CHECK:       @ %bb.0: @ %entry
+; CHECK-NEXT:    vbrsr.8 q0, q0, #0
+; CHECK-NEXT:    bx lr
+entry:
+  %0 = call <16 x i8> @llvm.bitreverse.v16i8(<16 x i8> %src)
+  ret <16 x i8> %0
+}
+
+declare <4 x i32> @llvm.bitreverse.v4i32(<4 x i32>)
+declare <8 x i16> @llvm.bitreverse.v8i16(<8 x i16>)
+declare <16 x i8> @llvm.bitreverse.v16i8(<16 x i8>)
+
Index: llvm/lib/Target/ARM/ARMInstrMVE.td
===================================================================
--- llvm/lib/Target/ARM/ARMInstrMVE.td
+++ llvm/lib/Target/ARM/ARMInstrMVE.td
@@ -3724,6 +3724,17 @@
 def MVE_VBRSR16 : MVE_VBRSR<"vbrsr", "16", 0b01>;
 def MVE_VBRSR32 : MVE_VBRSR<"vbrsr", "32", 0b10>;
 
+let Predicates = [HasMVEInt] in {
+  def : Pat<(v16i8 ( bitreverse (v16i8 MQPR:$val1))),
+            (v16i8 ( MVE_VBRSR8 (v16i8 MQPR:$val1), 0 ))>;
+
+  def : Pat<(v4i32 ( bitreverse (v4i32 MQPR:$val1))),
+            (v4i32 ( MVE_VBRSR32 (v4i32 MQPR:$val1), 0 ))>;
+
+  def : Pat<(v8i16 ( bitreverse (v8i16 MQPR:$val1))),
+            (v8i16 ( MVE_VBRSR16 (v8i16 MQPR:$val1), 0 ))>;
+}
+
 class MVE_VMUL_qr_int<string iname, string suffix,
                       bits<2> size, list<dag> pattern=[]>
   : MVE_qDest_rSrc<iname, suffix, pattern> {
Index: llvm/lib/Target/ARM/ARMISelLowering.cpp
===================================================================
--- llvm/lib/Target/ARM/ARMISelLowering.cpp
+++ llvm/lib/Target/ARM/ARMISelLowering.cpp
@@ -261,6 +261,7 @@
     setOperationAction(ISD::SETCC, VT, Custom);
     setOperationAction(ISD::CTLZ, VT, Legal);
     setOperationAction(ISD::CTTZ, VT, Custom);
+    setOperationAction(ISD::BITREVERSE, VT, Legal);
 
     // No native support for these.
     setOperationAction(ISD::UDIV, VT, Expand);


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