[SelectionDAG] Add tests for LKK algorithm

Added some tests testing urem and srem operations with a constant divisor.

Patch by TG908 (Tim Gymnich)

Differential Revision: https://reviews.llvm.org/D68421



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@373830 91177308-0d34-0410-b5e6-96231b3b80d8

test/CodeGen/AArch64/srem-lkk.ll

@@ -0,0 +1,149 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -mtriple=aarch64-unknown-linux-gnu < %s | FileCheck %s
+
+define i32 @fold_srem_positive_odd(i32 %x) {
+; CHECK-LABEL: fold_srem_positive_odd:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    mov w8, #37253
+; CHECK-NEXT:    movk w8, #44150, lsl #16
+; CHECK-NEXT:    smull x8, w0, w8
+; CHECK-NEXT:    lsr x8, x8, #32
+; CHECK-NEXT:    add w8, w8, w0
+; CHECK-NEXT:    asr w9, w8, #6
+; CHECK-NEXT:    add w8, w9, w8, lsr #31
+; CHECK-NEXT:    mov w9, #95
+; CHECK-NEXT:    msub w0, w8, w9, w0
+; CHECK-NEXT:    ret
+  %1 = srem i32 %x, 95
+  ret i32 %1
+}
+
+
+define i32 @fold_srem_positive_even(i32 %x) {
+; CHECK-LABEL: fold_srem_positive_even:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    mov w8, #36849
+; CHECK-NEXT:    movk w8, #15827, lsl #16
+; CHECK-NEXT:    smull x8, w0, w8
+; CHECK-NEXT:    lsr x9, x8, #63
+; CHECK-NEXT:    asr x8, x8, #40
+; CHECK-NEXT:    add w8, w8, w9
+; CHECK-NEXT:    mov w9, #1060
+; CHECK-NEXT:    msub w0, w8, w9, w0
+; CHECK-NEXT:    ret
+  %1 = srem i32 %x, 1060
+  ret i32 %1
+}
+
+
+define i32 @fold_srem_negative_odd(i32 %x) {
+; CHECK-LABEL: fold_srem_negative_odd:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    mov w8, #65445
+; CHECK-NEXT:    movk w8, #42330, lsl #16
+; CHECK-NEXT:    smull x8, w0, w8
+; CHECK-NEXT:    lsr x9, x8, #63
+; CHECK-NEXT:    asr x8, x8, #40
+; CHECK-NEXT:    add w8, w8, w9
+; CHECK-NEXT:    mov w9, #-723
+; CHECK-NEXT:    msub w0, w8, w9, w0
+; CHECK-NEXT:    ret
+  %1 = srem i32 %x, -723
+  ret i32 %1
+}
+
+
+define i32 @fold_srem_negative_even(i32 %x) {
+; CHECK-LABEL: fold_srem_negative_even:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    mov w8, #62439
+; CHECK-NEXT:    movk w8, #64805, lsl #16
+; CHECK-NEXT:    smull x8, w0, w8
+; CHECK-NEXT:    lsr x9, x8, #63
+; CHECK-NEXT:    asr x8, x8, #40
+; CHECK-NEXT:    add w8, w8, w9
+; CHECK-NEXT:    mov w9, #-22981
+; CHECK-NEXT:    msub w0, w8, w9, w0
+; CHECK-NEXT:    ret
+  %1 = srem i32 %x, -22981
+  ret i32 %1
+}
+
+
+; Don't fold if we can combine srem with sdiv.
+define i32 @combine_srem_sdiv(i32 %x) {
+; CHECK-LABEL: combine_srem_sdiv:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    mov w8, #37253
+; CHECK-NEXT:    movk w8, #44150, lsl #16
+; CHECK-NEXT:    smull x8, w0, w8
+; CHECK-NEXT:    lsr x8, x8, #32
+; CHECK-NEXT:    add w8, w8, w0
+; CHECK-NEXT:    asr w9, w8, #6
+; CHECK-NEXT:    add w8, w9, w8, lsr #31
+; CHECK-NEXT:    mov w9, #95
+; CHECK-NEXT:    msub w9, w8, w9, w0
+; CHECK-NEXT:    add w0, w9, w8
+; CHECK-NEXT:    ret
+  %1 = srem i32 %x, 95
+  %2 = sdiv i32 %x, 95
+  %3 = add i32 %1, %2
+  ret i32 %3
+}
+
+; Don't fold for divisors that are a power of two.
+define i32 @dont_fold_srem_power_of_two(i32 %x) {
+; CHECK-LABEL: dont_fold_srem_power_of_two:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    add w8, w0, #63 // =63
+; CHECK-NEXT:    cmp w0, #0 // =0
+; CHECK-NEXT:    csel w8, w8, w0, lt
+; CHECK-NEXT:    and w8, w8, #0xffffffc0
+; CHECK-NEXT:    sub w0, w0, w8
+; CHECK-NEXT:    ret
+  %1 = srem i32 %x, 64
+  ret i32 %1
+}
+
+; Don't fold if the divisor is one.
+define i32 @dont_fold_srem_one(i32 %x) {
+; CHECK-LABEL: dont_fold_srem_one:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    mov w0, wzr
+; CHECK-NEXT:    ret
+  %1 = srem i32 %x, 1
+  ret i32 %1
+}
+
+; Don't fold if the divisor is 2^31.
+define i32 @dont_fold_srem_i32_smax(i32 %x) {
+; CHECK-LABEL: dont_fold_srem_i32_smax:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    mov w8, #2147483647
+; CHECK-NEXT:    add w8, w0, w8
+; CHECK-NEXT:    cmp w0, #0 // =0
+; CHECK-NEXT:    csel w8, w8, w0, lt
+; CHECK-NEXT:    and w8, w8, #0x80000000
+; CHECK-NEXT:    add w0, w0, w8
+; CHECK-NEXT:    ret
+  %1 = srem i32 %x, 2147483648
+  ret i32 %1
+}
+
+; Don't fold i64 srem
+define i64 @dont_fold_srem_i64(i64 %x) {
+; CHECK-LABEL: dont_fold_srem_i64:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    mov x8, #58849
+; CHECK-NEXT:    movk x8, #48148, lsl #16
+; CHECK-NEXT:    movk x8, #33436, lsl #32
+; CHECK-NEXT:    movk x8, #21399, lsl #48
+; CHECK-NEXT:    smulh x8, x0, x8
+; CHECK-NEXT:    asr x9, x8, #5
+; CHECK-NEXT:    add x8, x9, x8, lsr #63
+; CHECK-NEXT:    mov w9, #98
+; CHECK-NEXT:    msub x0, x8, x9, x0
+; CHECK-NEXT:    ret
+  %1 = srem i64 %x, 98
+  ret i64 %1
+}