llvm/test/CodeGen/X86/udiv-const-optimization.ll

; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
; RUN: llc < %s -mtriple=x86_64-unknown-linux-gnu | FileCheck %s --check-prefix=X64
; RUN: llc < %s -mtriple=x86_64-unknown-linux-gnu -mattr=+bmi2 | FileCheck %s --check-prefix=X64-BMI2
; RUN: llc < %s -mtriple=i386-unknown-linux-gnu | FileCheck %s --check-prefix=X86

; Test optimization of 32-bit unsigned division by constants with 33-bit magic
; constants (IsAdd=true) on 64-bit targets. The optimization uses pre-shifted
; constants and 64x64->128 bit multiplication to reduce instruction count.

define i32 @udiv_by_7(i32 %x) nounwind {
; X64-LABEL: udiv_by_7:
; X64:       # %bb.0:
; X64-NEXT:    movl %edi, %eax
; X64-NEXT:    movabsq $2635249153617166336, %rcx # imm = 0x24924924A0000000
; X64-NEXT:    mulq %rcx
; X64-NEXT:    movq %rdx, %rax
; X64-NEXT:    # kill: def $eax killed $eax killed $rax
; X64-NEXT:    retq
;
; X64-BMI2-LABEL: udiv_by_7:
; X64-BMI2:       # %bb.0:
; X64-BMI2-NEXT:    movl %edi, %edx
; X64-BMI2-NEXT:    movabsq $2635249153617166336, %rax # imm = 0x24924924A0000000
; X64-BMI2-NEXT:    mulxq %rax, %rax, %rax
; X64-BMI2-NEXT:    # kill: def $eax killed $eax killed $rax
; X64-BMI2-NEXT:    retq
;
; X86-LABEL: udiv_by_7:
; X86:       # %bb.0:
; X86-NEXT:    movl {{[0-9]+}}(%esp), %ecx
; X86-NEXT:    movl $613566757, %edx # imm = 0x24924925
; X86-NEXT:    movl %ecx, %eax
; X86-NEXT:    mull %edx
; X86-NEXT:    subl %edx, %ecx
; X86-NEXT:    shrl %ecx
; X86-NEXT:    addl %edx, %ecx
; X86-NEXT:    shrl $2, %ecx
; X86-NEXT:    movl %ecx, %eax
; X86-NEXT:    retl
  %div = udiv i32 %x, 7
  ret i32 %div
}

define i32 @udiv_by_19(i32 %x) nounwind {
; X64-LABEL: udiv_by_19:
; X64:       # %bb.0:
; X64-NEXT:    movl %edi, %eax
; X64-NEXT:    movabsq $970881267157434368, %rcx # imm = 0xD79435E58000000
; X64-NEXT:    mulq %rcx
; X64-NEXT:    movq %rdx, %rax
; X64-NEXT:    # kill: def $eax killed $eax killed $rax
; X64-NEXT:    retq
;
; X64-BMI2-LABEL: udiv_by_19:
; X64-BMI2:       # %bb.0:
; X64-BMI2-NEXT:    movl %edi, %edx
; X64-BMI2-NEXT:    movabsq $970881267157434368, %rax # imm = 0xD79435E58000000
; X64-BMI2-NEXT:    mulxq %rax, %rax, %rax
; X64-BMI2-NEXT:    # kill: def $eax killed $eax killed $rax
; X64-BMI2-NEXT:    retq
;
; X86-LABEL: udiv_by_19:
; X86:       # %bb.0:
; X86-NEXT:    movl {{[0-9]+}}(%esp), %ecx
; X86-NEXT:    movl ${{-?[0-9]+}}, %edx # imm = 0xAF286BCB
; X86-NEXT:    movl %ecx, %eax
; X86-NEXT:    mull %edx
; X86-NEXT:    subl %edx, %ecx
; X86-NEXT:    shrl %ecx
; X86-NEXT:    addl %edx, %ecx
; X86-NEXT:    shrl $4, %ecx
; X86-NEXT:    movl %ecx, %eax
; X86-NEXT:    retl
  %div = udiv i32 %x, 19
  ret i32 %div
}

define i32 @udiv_by_21(i32 %x) nounwind {
; X64-LABEL: udiv_by_21:
; X64:       # %bb.0:
; X64-NEXT:    movl %edi, %eax
; X64-NEXT:    movabsq $878416384583794688, %rcx # imm = 0xC30C30C38000000
; X64-NEXT:    mulq %rcx
; X64-NEXT:    movq %rdx, %rax
; X64-NEXT:    # kill: def $eax killed $eax killed $rax
; X64-NEXT:    retq
;
; X64-BMI2-LABEL: udiv_by_21:
; X64-BMI2:       # %bb.0:
; X64-BMI2-NEXT:    movl %edi, %edx
; X64-BMI2-NEXT:    movabsq $878416384583794688, %rax # imm = 0xC30C30C38000000
; X64-BMI2-NEXT:    mulxq %rax, %rax, %rax
; X64-BMI2-NEXT:    # kill: def $eax killed $eax killed $rax
; X64-BMI2-NEXT:    retq
;
; X86-LABEL: udiv_by_21:
; X86:       # %bb.0:
; X86-NEXT:    movl {{[0-9]+}}(%esp), %ecx
; X86-NEXT:    movl ${{-?[0-9]+}}, %edx # imm = 0x86186187
; X86-NEXT:    movl %ecx, %eax
; X86-NEXT:    mull %edx
; X86-NEXT:    subl %edx, %ecx
; X86-NEXT:    shrl %ecx
; X86-NEXT:    addl %edx, %ecx
; X86-NEXT:    shrl $4, %ecx
; X86-NEXT:    movl %ecx, %eax
; X86-NEXT:    retl
  %div = udiv i32 %x, 21
  ret i32 %div
}

; Test non-optimized case: divisor that doesn't use IsAdd
define i32 @udiv_by_3(i32 %x) nounwind {
; X64-LABEL: udiv_by_3:
; X64:       # %bb.0:
; X64-NEXT:    movl %edi, %ecx
; X64-NEXT:    movl $2863311531, %eax # imm = 0xAAAAAAAB
; X64-NEXT:    imulq %rcx, %rax
; X64-NEXT:    shrq $33, %rax
; X64-NEXT:    # kill: def $eax killed $eax killed $rax
; X64-NEXT:    retq
;
; X64-BMI2-LABEL: udiv_by_3:
; X64-BMI2:       # %bb.0:
; X64-BMI2-NEXT:    movl %edi, %ecx
; X64-BMI2-NEXT:    movl $2863311531, %eax # imm = 0xAAAAAAAB
; X64-BMI2-NEXT:    imulq %rcx, %rax
; X64-BMI2-NEXT:    shrq $33, %rax
; X64-BMI2-NEXT:    # kill: def $eax killed $eax killed $rax
; X64-BMI2-NEXT:    retq
;
; X86-LABEL: udiv_by_3:
; X86:       # %bb.0:
; X86-NEXT:    movl ${{-?[0-9]+}}, %eax # imm = 0xAAAAAAAB
; X86-NEXT:    mull {{[0-9]+}}(%esp)
; X86-NEXT:    movl %edx, %eax
; X86-NEXT:    shrl %eax
; X86-NEXT:    retl
  %div = udiv i32 %x, 3
  ret i32 %div
}