Pre-commit test case for D101970

[Carrot]

Summary

This is a test case for D101970, which shows the optimization opportunity for

    lea (reg1, reg2), reg3
    sub reg3, reg4

to

    sub reg1, reg4
    sub reg2, reg4

[RKSimon]

LGTM

llvm/test/CodeGen/X86/lea-opt2.ll

+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc < %s -mtriple=x86_64-unknown | FileCheck %s
+
+; This file tests following optimization
+;
+;        leal    (%rdx,%rax), %esi
+;        subl    %esi, %ecx
+;
+; can be transformed to
+;
+;        subl    %edx, %ecx
+;        subl    %eax, %ecx
+
+; TODO: replace lea with sub.
+; C - (A + B)   -->    C - A - B
+define i32 @test1(i32* %p, i32 %a, i32 %b, i32 %c) {
+; CHECK-LABEL: test1:
+; CHECK:       # %bb.0: # %entry
+; CHECK-NEXT:    # kill: def $edx killed $edx def $rdx
+; CHECK-NEXT:    movl %esi, %eax
+; CHECK-NEXT:    leal (%rdx,%rax), %esi
+; CHECK-NEXT:    subl %esi, %ecx
+; CHECK-NEXT:    movl %ecx, (%rdi)
+; CHECK-NEXT:    subl %edx, %eax
+; CHECK-NEXT:    # kill: def $eax killed $eax killed $rax
+; CHECK-NEXT:    retq
+entry:
+  %0 = add i32 %b, %a
+  %sub = sub i32 %c, %0
+  store i32 %sub, i32* %p, align 4
+  %sub1 = sub i32 %a, %b
+  ret i32 %sub1
+}
+
+; TODO: replace lea with add.
+; (A + B) + C   -->    C + A + B
+define i32 @test2(i32* %p, i32 %a, i32 %b, i32 %c) {
+; CHECK-LABEL: test2:
+; CHECK:       # %bb.0: # %entry
+; CHECK-NEXT:    # kill: def $edx killed $edx def $rdx
+; CHECK-NEXT:    movl %esi, %eax
+; CHECK-NEXT:    leal (%rax,%rdx), %esi
+; CHECK-NEXT:    addl %ecx, %esi
+; CHECK-NEXT:    movl %esi, (%rdi)
+; CHECK-NEXT:    subl %edx, %eax
+; CHECK-NEXT:    # kill: def $eax killed $eax killed $rax
+; CHECK-NEXT:    retq
+entry:
+  %0 = add i32 %a, %b
+  %1 = add i32 %c, %0
+  store i32 %1, i32* %p, align 4
+  %sub1 = sub i32 %a, %b
+  ret i32 %sub1
+}
+
+; TODO: replace lea with add.
+; C + (A + B)   -->    C + A + B
+define i32 @test3(i32* %p, i32 %a, i32 %b, i32 %c) {
+; CHECK-LABEL: test3:
+; CHECK:       # %bb.0: # %entry
+; CHECK-NEXT:    # kill: def $edx killed $edx def $rdx
+; CHECK-NEXT:    movl %esi, %eax
+; CHECK-NEXT:    leal (%rax,%rdx), %esi
+; CHECK-NEXT:    addl %ecx, %esi
+; CHECK-NEXT:    movl %esi, (%rdi)
+; CHECK-NEXT:    subl %edx, %eax
+; CHECK-NEXT:    # kill: def $eax killed $eax killed $rax
+; CHECK-NEXT:    retq
+entry:
+  %0 = add i32 %a, %b
+  %1 = add i32 %0, %c
+  store i32 %1, i32* %p, align 4
+  %sub1 = sub i32 %a, %b
+  ret i32 %sub1
+}
+
+; (A + B) - C
+; Can't be converted to A - C + B without introduce MOV
+define i32 @test4(i32* %p, i32 %a, i32 %b, i32 %c) {
+; CHECK-LABEL: test4:
+; CHECK:       # %bb.0: # %entry
+; CHECK-NEXT:    # kill: def $edx killed $edx def $rdx
+; CHECK-NEXT:    movl %esi, %eax
+; CHECK-NEXT:    leal (%rdx,%rax), %esi
+; CHECK-NEXT:    subl %ecx, %esi
+; CHECK-NEXT:    movl %esi, (%rdi)
+; CHECK-NEXT:    subl %edx, %eax
+; CHECK-NEXT:    # kill: def $eax killed $eax killed $rax
+; CHECK-NEXT:    retq
+entry:
+  %0 = add i32 %b, %a
+  %sub = sub i32 %0, %c
+  store i32 %sub, i32* %p, align 4
+  %sub1 = sub i32 %a, %b
+  ret i32 %sub1
+}
+
+; TODO: replace lea with sub.
+define i64 @test5(i64* %p, i64 %a, i64 %b, i64 %c) {
+; CHECK-LABEL: test5:
+; CHECK:       # %bb.0: # %entry
+; CHECK-NEXT:    movq (%rdi), %rax
+; CHECK-NEXT:    leaq (%rdx,%rax), %rsi
+; CHECK-NEXT:    subq %rsi, %rcx
+; CHECK-NEXT:    movq %rcx, (%rdi)
+; CHECK-NEXT:    subq %rdx, %rax
+; CHECK-NEXT:    retq
+entry:
+  %ld = load i64, i64* %p, align 8
+  %0 = add i64 %b, %ld
+  %sub = sub i64 %c, %0
+  store i64 %sub, i64* %p, align 8
+  %sub1 = sub i64 %ld, %b
+  ret i64 %sub1
+}
+
+; TODO: replace lea with add.
+define i64 @test6(i64* %p, i64 %a, i64 %b, i64 %c) {
+; CHECK-LABEL: test6:
+; CHECK:       # %bb.0: # %entry
+; CHECK-NEXT:    movq (%rdi), %rax
+; CHECK-NEXT:    leaq (%rdx,%rax), %rsi
+; CHECK-NEXT:    addq %rcx, %rsi
+; CHECK-NEXT:    movq %rsi, (%rdi)
+; CHECK-NEXT:    subq %rdx, %rax
+; CHECK-NEXT:    retq
+entry:
+  %ld = load i64, i64* %p, align 8
+  %0 = add i64 %b, %ld
+  %1 = add i64 %0, %c
+  store i64 %1, i64* %p, align 8
+  %sub1 = sub i64 %ld, %b
+  ret i64 %sub1
+}
+
+; TODO: replace lea with add.
+define i64 @test7(i64* %p, i64 %a, i64 %b, i64 %c) {
+; CHECK-LABEL: test7:
+; CHECK:       # %bb.0: # %entry
+; CHECK-NEXT:    movq (%rdi), %rax
+; CHECK-NEXT:    leaq (%rdx,%rax), %rsi
+; CHECK-NEXT:    addq %rcx, %rsi
+; CHECK-NEXT:    movq %rsi, (%rdi)
+; CHECK-NEXT:    subq %rdx, %rax
+; CHECK-NEXT:    retq
+entry:
+  %ld = load i64, i64* %p, align 8
+  %0 = add i64 %b, %ld
+  %1 = add i64 %c, %0
+  store i64 %1, i64* %p, align 8
+  %sub1 = sub i64 %ld, %b
+  ret i64 %sub1
+}
+