1; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 3 2; RUN: llc < %s -mtriple=x86_64-unknown | FileCheck %s 3 4; When optimize for size, the constant $858993459 is moved into a register, 5; and use that register in following two andl instructions. 6 7define i32 @cnt32_optsize(i32 %x) nounwind readnone optsize { 8; CHECK-LABEL: cnt32_optsize: 9; CHECK: # %bb.0: 10; CHECK-NEXT: movl %edi, %eax 11; CHECK-NEXT: shrl %eax 12; CHECK-NEXT: andl $1431655765, %eax # imm = 0x55555555 13; CHECK-NEXT: subl %eax, %edi 14; CHECK-NEXT: movl $858993459, %eax # imm = 0x33333333 15; CHECK-NEXT: movl %edi, %ecx 16; CHECK-NEXT: andl %eax, %ecx 17; CHECK-NEXT: shrl $2, %edi 18; CHECK-NEXT: andl %eax, %edi 19; CHECK-NEXT: addl %ecx, %edi 20; CHECK-NEXT: movl %edi, %eax 21; CHECK-NEXT: shrl $4, %eax 22; CHECK-NEXT: addl %edi, %eax 23; CHECK-NEXT: andl $252645135, %eax # imm = 0xF0F0F0F 24; CHECK-NEXT: imull $16843009, %eax, %eax # imm = 0x1010101 25; CHECK-NEXT: shrl $24, %eax 26; CHECK-NEXT: retq 27 %cnt = tail call i32 @llvm.ctpop.i32(i32 %x) 28 ret i32 %cnt 29} 30 31; When optimize for speed, the constant $858993459 can be directly folded into 32; two andl instructions. 33 34define i32 @cnt32_optspeed(i32 %x) nounwind readnone { 35; CHECK-LABEL: cnt32_optspeed: 36; CHECK: # %bb.0: 37; CHECK-NEXT: movl %edi, %eax 38; CHECK-NEXT: shrl %eax 39; CHECK-NEXT: andl $1431655765, %eax # imm = 0x55555555 40; CHECK-NEXT: subl %eax, %edi 41; CHECK-NEXT: movl %edi, %eax 42; CHECK-NEXT: andl $858993459, %eax # imm = 0x33333333 43; CHECK-NEXT: shrl $2, %edi 44; CHECK-NEXT: andl $858993459, %edi # imm = 0x33333333 45; CHECK-NEXT: addl %eax, %edi 46; CHECK-NEXT: movl %edi, %eax 47; CHECK-NEXT: shrl $4, %eax 48; CHECK-NEXT: addl %edi, %eax 49; CHECK-NEXT: andl $252645135, %eax # imm = 0xF0F0F0F 50; CHECK-NEXT: imull $16843009, %eax, %eax # imm = 0x1010101 51; CHECK-NEXT: shrl $24, %eax 52; CHECK-NEXT: retq 53 %cnt = tail call i32 @llvm.ctpop.i32(i32 %x) 54 ret i32 %cnt 55} 56 57declare i32 @llvm.ctpop.i32(i32) nounwind readnone 58