[PowerPC] Improve code gen for vector add

Improve codegen for vectors modulo additions.

Reviewed By: nemanjai

Differential Revision: https://reviews.llvm.org/D154447

Author: nemanjai

llvm/lib/Target/PowerPC/PPCInstrAltivec.td

@@ -1161,6 +1161,13 @@ def : Pat<(v8i16 (srl (sub v8i16:$vA, (v8i16 (bitconvert(vnot v4i32:$vB)))),
 def : Pat<(v16i8 (srl (sub v16i8:$vA, (v16i8 (bitconvert(vnot v4i32:$vB)))),
           (v16i8 (immEQOneV)))), (v16i8 (VAVGUB $vA, $vB))>;
 
+def : Pat<(v16i8 (shl v16i8:$vA, (v16i8 (immEQOneV)))),
+          (v16i8 (VADDUBM $vA, $vA))>;
+def : Pat<(v8i16 (shl v8i16:$vA, (v8i16 (immEQOneV)))),
+          (v8i16 (VADDUHM $vA, $vA))>;
+def : Pat<(v4i32 (shl v4i32:$vA, (v4i32 (immEQOneV)))),
+          (v4i32 (VADDUWM $vA, $vA))>;
+
 } // end HasAltivec
 
 // [PO VRT VRA VRB 1 PS XO], "_o" means CR6 is set.

llvm/test/CodeGen/PowerPC/optimize-vector.ll

@@ -1,13 +1,12 @@
 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 2
 ; RUN: llc -verify-machineinstrs -mtriple=powerpc64le-unknown-linux-gnu \
-; RUN:   -mcpu=pwr7 -ppc-asm-full-reg-names -ppc-vsr-nums-as-vr < %s | \
+; RUN:   -mcpu=pwr8 -ppc-asm-full-reg-names -ppc-vsr-nums-as-vr < %s | \
 ; RUN:   FileCheck %s
 
 define dso_local <16 x i8> @x2(<16 x i8> noundef %x) {
 ; CHECK-LABEL: x2:
 ; CHECK:       # %bb.0: # %entry
-; CHECK-NEXT:    vspltisb v3, 1
-; CHECK-NEXT:    vslb v2, v2, v3
+; CHECK-NEXT:    vaddubm v2, v2, v2
 ; CHECK-NEXT:    blr
 entry:
   %add = shl <16 x i8> %x, <i8 1, i8 1, i8 1, i8 1, i8 1, i8 1, i8 1, i8 1, i8 1, i8 1, i8 1, i8 1, i8 1, i8 1, i8 1, i8 1>
@@ -17,8 +16,7 @@ entry:
 define dso_local <8 x i16> @x2h(<8 x i16> noundef %x) {
 ; CHECK-LABEL: x2h:
 ; CHECK:       # %bb.0: # %entry
-; CHECK-NEXT:    vspltish v3, 1
-; CHECK-NEXT:    vslh v2, v2, v3
+; CHECK-NEXT:    vadduhm v2, v2, v2
 ; CHECK-NEXT:    blr
 entry:
   %add = shl <8 x i16> %x, <i16 1, i16 1, i16 1, i16 1, i16 1, i16 1, i16 1, i16 1>
@@ -28,10 +26,22 @@ entry:
 define dso_local <4 x i32> @x2w(<4 x i32> noundef %x) {
 ; CHECK-LABEL: x2w:
 ; CHECK:       # %bb.0: # %entry
-; CHECK-NEXT:    vspltisw v3, 1
-; CHECK-NEXT:    vslw v2, v2, v3
+; CHECK-NEXT:    vadduwm v2, v2, v2
 ; CHECK-NEXT:    blr
 entry:
   %add = shl <4 x i32> %x, <i32 1, i32 1, i32 1, i32 1>
   ret <4 x i32> %add
 }
+
+define dso_local <2 x i64> @x2d(<2 x i64> noundef %x) {
+; CHECK-LABEL: x2d:
+; CHECK:       # %bb.0: # %entry
+; CHECK-NEXT:    addis r3, r2, .LCPI3_0@toc@ha
+; CHECK-NEXT:    addi r3, r3, .LCPI3_0@toc@l
+; CHECK-NEXT:    lxvd2x v3, 0, r3
+; CHECK-NEXT:    vsld v2, v2, v3
+; CHECK-NEXT:    blr
+entry:
+  %add = shl <2 x i64> %x, <i64 1, i64 1>
+  ret <2 x i64> %add
+}