[PATCH] D147423: [LoongArch] Optimize 32-bit addition with ALSL_W on LoongArch64

[Ben Shi via Phabricator via llvm-commits]

benshi001 created this revision.
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Optimize 32-bit 'x+(y<<i)' to (ALSL_W y, x, i) on LoongArch64,
in which 'i' in [1, 2, 3, 4].


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D147423

Files:
  llvm/lib/Target/LoongArch/LoongArchInstrInfo.td
  llvm/test/CodeGen/LoongArch/ir-instruction/mul.ll


Index: llvm/test/CodeGen/LoongArch/ir-instruction/mul.ll
===================================================================
--- llvm/test/CodeGen/LoongArch/ir-instruction/mul.ll
+++ llvm/test/CodeGen/LoongArch/ir-instruction/mul.ll
@@ -1029,9 +1029,8 @@
 ;
 ; LA64-LABEL: mul_i32_4098:
 ; LA64:       # %bb.0:
-; LA64-NEXT:    slli.d $a1, $a0, 1
-; LA64-NEXT:    slli.d $a0, $a0, 12
-; LA64-NEXT:    add.w $a0, $a0, $a1
+; LA64-NEXT:    slli.d $a1, $a0, 12
+; LA64-NEXT:    alsl.w $a0, $a0, $a1, 1
 ; LA64-NEXT:    ret
   %b = mul i32 %a, 4098
   ret i32 %b
@@ -1046,9 +1045,8 @@
 ;
 ; LA64-LABEL: mul_i32_4100:
 ; LA64:       # %bb.0:
-; LA64-NEXT:    slli.d $a1, $a0, 2
-; LA64-NEXT:    slli.d $a0, $a0, 12
-; LA64-NEXT:    add.w $a0, $a0, $a1
+; LA64-NEXT:    slli.d $a1, $a0, 12
+; LA64-NEXT:    alsl.w $a0, $a0, $a1, 2
 ; LA64-NEXT:    ret
   %b = mul i32 %a, 4100
   ret i32 %b
@@ -1063,9 +1061,8 @@
 ;
 ; LA64-LABEL: mul_i32_4104:
 ; LA64:       # %bb.0:
-; LA64-NEXT:    slli.d $a1, $a0, 3
-; LA64-NEXT:    slli.d $a0, $a0, 12
-; LA64-NEXT:    add.w $a0, $a0, $a1
+; LA64-NEXT:    slli.d $a1, $a0, 12
+; LA64-NEXT:    alsl.w $a0, $a0, $a1, 3
 ; LA64-NEXT:    ret
   %b = mul i32 %a, 4104
   ret i32 %b
@@ -1080,9 +1077,8 @@
 ;
 ; LA64-LABEL: mul_i32_4112:
 ; LA64:       # %bb.0:
-; LA64-NEXT:    slli.d $a1, $a0, 4
-; LA64-NEXT:    slli.d $a0, $a0, 12
-; LA64-NEXT:    add.w $a0, $a0, $a1
+; LA64-NEXT:    slli.d $a1, $a0, 12
+; LA64-NEXT:    alsl.w $a0, $a0, $a1, 4
 ; LA64-NEXT:    ret
   %b = mul i32 %a, 4112
   ret i32 %b
Index: llvm/lib/Target/LoongArch/LoongArchInstrInfo.td
===================================================================
--- llvm/lib/Target/LoongArch/LoongArchInstrInfo.td
+++ llvm/lib/Target/LoongArch/LoongArchInstrInfo.td
@@ -1075,6 +1075,8 @@
 let Predicates = [IsLA64] in {
 def : Pat<(add GPR:$rk, (shl GPR:$rj, uimm2_plus1:$imm2)),
           (ALSL_D GPR:$rj, GPR:$rk, uimm2_plus1:$imm2)>;
+def : Pat<(sext_inreg (add GPR:$rk, (shl GPR:$rj, uimm2_plus1:$imm2)), i32),
+          (ALSL_W GPR:$rj, GPR:$rk, uimm2_plus1:$imm2)>;
 def : Pat<(loongarch_bstrpick (add GPR:$rk, (shl GPR:$rj, uimm2_plus1:$imm2)),
                               (i64 31), (i64 0)),
           (ALSL_WU GPR:$rj, GPR:$rk, uimm2_plus1:$imm2)>;


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