[RISCV][test] Add a new codegen test of add-mul transform

[benshi001]

Summary

This case will show whether (mul (add x, c1), c2) can be transformed
to (add (mul x, c2), c1*c2) according to different c1/c2 pairs.

[benshi001]

This patch will show the optimization by my previous patch https://reviews.llvm.org/D83153

[lenary]

LGTM!

Please ask for commit access and land this yourself. There's more about this, and what that entails, in this document: https://llvm.org/docs/DeveloperPolicy.html

[MaskRay]

Optional: you can add [test] to the subject, i.e. [RISCV][test] to make it clear this patch is completely about tests. This is even stronger than NFC (non-functional change).

llvm/test/CodeGen/RISCV/addimm-mulimm.ll

2

It'd be better adding a file-level comment.

[asb]

llvm/test/CodeGen/RISCV/addimm-mulimm.ll

2

+1 on adding a comment to this file explaining what it's aiming to demonstrate

llvm/test/CodeGen/RISCV/addimm-mulimm.ll

+;; Test that (mul (add x, c1), c2) can be transformed to
+;; (add (mul x, c2), c1*c2) if profitable.
+
+; RUN: llc -mtriple=riscv32 -mattr=+m -verify-machineinstrs < %s \
+; RUN:   | FileCheck -check-prefix=RV32IM %s
+; RUN: llc -mtriple=riscv64 -mattr=+m -verify-machineinstrs < %s \
+; RUN:   | FileCheck -check-prefix=RV64IM %s
+
+define signext i32 @add_mul_trans_accept_1(i32 %x) {
+; RV32IM-LABEL: add_mul_trans_accept_1
+; RV32IM:       # %bb.0:
+; RV32IM-NEXT:    addi a1, zero, 11
+; RV32IM-NEXT:    mul a0, a0, a1
+; RV32IM-NEXT:    addi a0, a0, 407
+; RV32IM-NEXT:    ret
+;
+; RV64IM-LABEL: add_mul_trans_accept_1
+; RV64IM:       # %bb.0:
+; RV64IM-NEXT:    addi a1, zero, 11
+; RV64IM-NEXT:    mul a0, a0, a1
+; RV64IM-NEXT:    addiw a0, a0, 407
+; RV64IM-NEXT:    ret
+  %tmp0 = add i32 %x, 37
+  %tmp1 = mul i32 %tmp0, 11
+  ret i32 %tmp1
+}
+
+define signext i32 @add_mul_trans_accept_2(i32 %x) {
+; RV32IM-LABEL: add_mul_trans_accept_2
+; RV32IM:       # %bb.0:
+; RV32IM-NEXT:    addi a1, zero, 13
+; RV32IM-NEXT:    mul a0, a0, a1
+; RV32IM-NEXT:    lui a1, 28
+; RV32IM-NEXT:    addi a1, a1, 1701
+; RV32IM-NEXT:    add a0, a0, a1
+; RV32IM-NEXT:    ret
+;
+; RV64IM-LABEL: add_mul_trans_accept_2
+; RV64IM:       # %bb.0:
+; RV64IM-NEXT:    addi a1, zero, 13
+; RV64IM-NEXT:    mul a0, a0, a1
+; RV64IM-NEXT:    lui a1, 28
+; RV64IM-NEXT:    addiw a1, a1, 1701
+; RV64IM-NEXT:    addw a0, a0, a1
+; RV64IM-NEXT:    ret
+  %tmp0 = add i32 %x, 8953
+  %tmp1 = mul i32 %tmp0, 13
+  ret i32 %tmp1
+}
+
+define signext i32 @add_mul_trans_reject_1(i32 %x) {
+; RV32IM-LABEL: add_mul_trans_reject_1
+; RV32IM:       # %bb.0:
+; RV32IM-NEXT:    addi a1, zero, 19
+; RV32IM-NEXT:    mul a0, a0, a1
+; RV32IM-NEXT:    lui a1, 9
+; RV32IM-NEXT:    addi a1, a1, 585
+; RV32IM-NEXT:    add a0, a0, a1
+; RV32IM-NEXT:    ret
+;
+; RV64IM-LABEL: add_mul_trans_reject_1
+; RV64IM:       # %bb.0:
+; RV64IM-NEXT:    addi a1, zero, 19
+; RV64IM-NEXT:    mul a0, a0, a1
+; RV64IM-NEXT:    lui a1, 9
+; RV64IM-NEXT:    addiw a1, a1, 585
+; RV64IM-NEXT:    addw a0, a0, a1
+; RV64IM-NEXT:    ret
+  %tmp0 = add i32 %x, 1971
+  %tmp1 = mul i32 %tmp0, 19
+  ret i32 %tmp1
+}
+
+define signext i32 @add_mul_trans_reject_2(i32 %x) {
+; RV32IM:       # %bb.0:
+; RV32IM-NEXT:    lui a1, 792
+; RV32IM-NEXT:    addi a1, a1, -1709
+; RV32IM-NEXT:    mul a0, a0, a1
+; RV32IM-NEXT:    lui a1, 1014660
+; RV32IM-NEXT:    addi a1, a1, -1891
+; RV32IM-NEXT:    add a0, a0, a1
+; RV32IM-NEXT:    ret
+;
+; RV64IM:       # %bb.0:
+; RV64IM-NEXT:    lui a1, 792
+; RV64IM-NEXT:    addiw a1, a1, -1709
+; RV64IM-NEXT:    mul a0, a0, a1
+; RV64IM-NEXT:    lui a1, 1014660
+; RV64IM-NEXT:    addiw a1, a1, -1891
+; RV64IM-NEXT:    addw a0, a0, a1
+; RV64IM-NEXT:    ret
+  %tmp0 = add i32 %x, 1841231
+  %tmp1 = mul i32 %tmp0, 3242323
+  ret i32 %tmp1
+}