; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py ; RUN: llc < %s -mtriple=x86_64-unknown-unknown | FileCheck %s ; Select of constants: control flow / conditional moves can always be replaced by logic+math (but may not be worth it?). ; Test the zeroext/signext variants of each pattern to see if that makes a difference. ; select Cond, 0, 1 --> zext (!Cond) define i32 @select_0_or_1(i1 %cond) { ; CHECK-LABEL: select_0_or_1: ; CHECK: # %bb.0: ; CHECK-NEXT: notb %dil ; CHECK-NEXT: movzbl %dil, %eax ; CHECK-NEXT: andl $1, %eax ; CHECK-NEXT: retq %sel = select i1 %cond, i32 0, i32 1 ret i32 %sel } define i32 @select_0_or_1_zeroext(i1 zeroext %cond) { ; CHECK-LABEL: select_0_or_1_zeroext: ; CHECK: # %bb.0: ; CHECK-NEXT: xorb $1, %dil ; CHECK-NEXT: movzbl %dil, %eax ; CHECK-NEXT: retq %sel = select i1 %cond, i32 0, i32 1 ret i32 %sel } define i32 @select_0_or_1_signext(i1 signext %cond) { ; CHECK-LABEL: select_0_or_1_signext: ; CHECK: # %bb.0: ; CHECK-NEXT: notb %dil ; CHECK-NEXT: movzbl %dil, %eax ; CHECK-NEXT: andl $1, %eax ; CHECK-NEXT: retq %sel = select i1 %cond, i32 0, i32 1 ret i32 %sel } ; select Cond, 1, 0 --> zext (Cond) define i32 @select_1_or_0(i1 %cond) { ; CHECK-LABEL: select_1_or_0: ; CHECK: # %bb.0: ; CHECK-NEXT: andl $1, %edi ; CHECK-NEXT: movl %edi, %eax ; CHECK-NEXT: retq %sel = select i1 %cond, i32 1, i32 0 ret i32 %sel } define i32 @select_1_or_0_zeroext(i1 zeroext %cond) { ; CHECK-LABEL: select_1_or_0_zeroext: ; CHECK: # %bb.0: ; CHECK-NEXT: movl %edi, %eax ; CHECK-NEXT: retq %sel = select i1 %cond, i32 1, i32 0 ret i32 %sel } define i32 @select_1_or_0_signext(i1 signext %cond) { ; CHECK-LABEL: select_1_or_0_signext: ; CHECK: # %bb.0: ; CHECK-NEXT: andl $1, %edi ; CHECK-NEXT: movl %edi, %eax ; CHECK-NEXT: retq %sel = select i1 %cond, i32 1, i32 0 ret i32 %sel } ; select Cond, 0, -1 --> sext (!Cond) define i32 @select_0_or_neg1(i1 %cond) { ; CHECK-LABEL: select_0_or_neg1: ; CHECK: # %bb.0: ; CHECK-NEXT: # kill: def %edi killed %edi def %rdi ; CHECK-NEXT: andl $1, %edi ; CHECK-NEXT: leal -1(%rdi), %eax ; CHECK-NEXT: retq %sel = select i1 %cond, i32 0, i32 -1 ret i32 %sel } define i32 @select_0_or_neg1_zeroext(i1 zeroext %cond) { ; CHECK-LABEL: select_0_or_neg1_zeroext: ; CHECK: # %bb.0: ; CHECK-NEXT: # kill: def %edi killed %edi def %rdi ; CHECK-NEXT: leal -1(%rdi), %eax ; CHECK-NEXT: retq %sel = select i1 %cond, i32 0, i32 -1 ret i32 %sel } define i32 @select_0_or_neg1_signext(i1 signext %cond) { ; CHECK-LABEL: select_0_or_neg1_signext: ; CHECK: # %bb.0: ; CHECK-NEXT: notl %edi ; CHECK-NEXT: movl %edi, %eax ; CHECK-NEXT: retq %sel = select i1 %cond, i32 0, i32 -1 ret i32 %sel } ; select Cond, -1, 0 --> sext (Cond) define i32 @select_neg1_or_0(i1 %cond) { ; CHECK-LABEL: select_neg1_or_0: ; CHECK: # %bb.0: ; CHECK-NEXT: andl $1, %edi ; CHECK-NEXT: negl %edi ; CHECK-NEXT: movl %edi, %eax ; CHECK-NEXT: retq %sel = select i1 %cond, i32 -1, i32 0 ret i32 %sel } define i32 @select_neg1_or_0_zeroext(i1 zeroext %cond) { ; CHECK-LABEL: select_neg1_or_0_zeroext: ; CHECK: # %bb.0: ; CHECK-NEXT: negl %edi ; CHECK-NEXT: movl %edi, %eax ; CHECK-NEXT: retq %sel = select i1 %cond, i32 -1, i32 0 ret i32 %sel } define i32 @select_neg1_or_0_signext(i1 signext %cond) { ; CHECK-LABEL: select_neg1_or_0_signext: ; CHECK: # %bb.0: ; CHECK-NEXT: movl %edi, %eax ; CHECK-NEXT: retq %sel = select i1 %cond, i32 -1, i32 0 ret i32 %sel } ; select Cond, C+1, C --> add (zext Cond), C define i32 @select_Cplus1_C(i1 %cond) { ; CHECK-LABEL: select_Cplus1_C: ; CHECK: # %bb.0: ; CHECK-NEXT: # kill: def %edi killed %edi def %rdi ; CHECK-NEXT: andl $1, %edi ; CHECK-NEXT: leal 41(%rdi), %eax ; CHECK-NEXT: retq %sel = select i1 %cond, i32 42, i32 41 ret i32 %sel } define i32 @select_Cplus1_C_zeroext(i1 zeroext %cond) { ; CHECK-LABEL: select_Cplus1_C_zeroext: ; CHECK: # %bb.0: ; CHECK-NEXT: # kill: def %edi killed %edi def %rdi ; CHECK-NEXT: leal 41(%rdi), %eax ; CHECK-NEXT: retq %sel = select i1 %cond, i32 42, i32 41 ret i32 %sel } define i32 @select_Cplus1_C_signext(i1 signext %cond) { ; CHECK-LABEL: select_Cplus1_C_signext: ; CHECK: # %bb.0: ; CHECK-NEXT: movl $41, %eax ; CHECK-NEXT: subl %edi, %eax ; CHECK-NEXT: retq %sel = select i1 %cond, i32 42, i32 41 ret i32 %sel } ; select Cond, C, C+1 --> add (sext Cond), C define i32 @select_C_Cplus1(i1 %cond) { ; CHECK-LABEL: select_C_Cplus1: ; CHECK: # %bb.0: ; CHECK-NEXT: andl $1, %edi ; CHECK-NEXT: movl $42, %eax ; CHECK-NEXT: subl %edi, %eax ; CHECK-NEXT: retq %sel = select i1 %cond, i32 41, i32 42 ret i32 %sel } define i32 @select_C_Cplus1_zeroext(i1 zeroext %cond) { ; CHECK-LABEL: select_C_Cplus1_zeroext: ; CHECK: # %bb.0: ; CHECK-NEXT: movl $42, %eax ; CHECK-NEXT: subl %edi, %eax ; CHECK-NEXT: retq %sel = select i1 %cond, i32 41, i32 42 ret i32 %sel } define i32 @select_C_Cplus1_signext(i1 signext %cond) { ; CHECK-LABEL: select_C_Cplus1_signext: ; CHECK: # %bb.0: ; CHECK-NEXT: andl $1, %edi ; CHECK-NEXT: movl $42, %eax ; CHECK-NEXT: subl %edi, %eax ; CHECK-NEXT: retq %sel = select i1 %cond, i32 41, i32 42 ret i32 %sel } ; If the constants differ by a small multiplier, use LEA. ; select Cond, C1, C2 --> add (mul (zext Cond), C1-C2), C2 --> LEA C2(Cond * (C1-C2)) define i32 @select_lea_2(i1 zeroext %cond) { ; CHECK-LABEL: select_lea_2: ; CHECK: # %bb.0: ; CHECK-NEXT: xorb $1, %dil ; CHECK-NEXT: movzbl %dil, %eax ; CHECK-NEXT: leal -1(%rax,%rax), %eax ; CHECK-NEXT: retq %sel = select i1 %cond, i32 -1, i32 1 ret i32 %sel } define i64 @select_lea_3(i1 zeroext %cond) { ; CHECK-LABEL: select_lea_3: ; CHECK: # %bb.0: ; CHECK-NEXT: xorb $1, %dil ; CHECK-NEXT: movzbl %dil, %eax ; CHECK-NEXT: leaq -2(%rax,%rax,2), %rax ; CHECK-NEXT: retq %sel = select i1 %cond, i64 -2, i64 1 ret i64 %sel } define i32 @select_lea_5(i1 zeroext %cond) { ; CHECK-LABEL: select_lea_5: ; CHECK: # %bb.0: ; CHECK-NEXT: xorb $1, %dil ; CHECK-NEXT: movzbl %dil, %eax ; CHECK-NEXT: leal -2(%rax,%rax,4), %eax ; CHECK-NEXT: retq %sel = select i1 %cond, i32 -2, i32 3 ret i32 %sel } define i64 @select_lea_9(i1 zeroext %cond) { ; CHECK-LABEL: select_lea_9: ; CHECK: # %bb.0: ; CHECK-NEXT: xorb $1, %dil ; CHECK-NEXT: movzbl %dil, %eax ; CHECK-NEXT: leaq -7(%rax,%rax,8), %rax ; CHECK-NEXT: retq %sel = select i1 %cond, i64 -7, i64 2 ret i64 %sel } ; Should this be 'sbb x,x' or 'sbb 0,x' with simpler LEA or add? define i64 @sel_1_2(i64 %x, i64 %y) { ; CHECK-LABEL: sel_1_2: ; CHECK: # %bb.0: ; CHECK-NEXT: cmpq $42, %rdi ; CHECK-NEXT: sbbq $0, %rsi ; CHECK-NEXT: leaq 2(%rsi), %rax ; CHECK-NEXT: retq %cmp = icmp ult i64 %x, 42 %sel = select i1 %cmp, i64 1, i64 2 %sub = add i64 %sel, %y ret i64 %sub } ; No LEA with 8-bit, but this shouldn't need branches or cmov. define i8 @sel_1_neg1(i32 %x) { ; CHECK-LABEL: sel_1_neg1: ; CHECK: # %bb.0: ; CHECK-NEXT: cmpl $42, %edi ; CHECK-NEXT: setg %al ; CHECK-NEXT: shlb $2, %al ; CHECK-NEXT: decb %al ; CHECK-NEXT: retq %cmp = icmp sgt i32 %x, 42 %sel = select i1 %cmp, i8 3, i8 -1 ret i8 %sel } ; We get an LEA for 16-bit because we ignore the high-bits. define i16 @sel_neg1_1(i32 %x) { ; CHECK-LABEL: sel_neg1_1: ; CHECK: # %bb.0: ; CHECK-NEXT: xorl %eax, %eax ; CHECK-NEXT: cmpl $43, %edi ; CHECK-NEXT: setl %al ; CHECK-NEXT: leal -1(,%rax,4), %eax ; CHECK-NEXT: # kill: def %ax killed %ax killed %eax ; CHECK-NEXT: retq %cmp = icmp sgt i32 %x, 42 %sel = select i1 %cmp, i16 -1, i16 3 ret i16 %sel } ; If the comparison is available, the predicate can be inverted. define i32 @sel_1_neg1_32(i32 %x) { ; CHECK-LABEL: sel_1_neg1_32: ; CHECK: # %bb.0: ; CHECK-NEXT: xorl %eax, %eax ; CHECK-NEXT: cmpl $42, %edi ; CHECK-NEXT: setg %al ; CHECK-NEXT: leal -1(%rax,%rax,8), %eax ; CHECK-NEXT: retq %cmp = icmp sgt i32 %x, 42 %sel = select i1 %cmp, i32 8, i32 -1 ret i32 %sel } define i32 @sel_neg1_1_32(i32 %x) { ; CHECK-LABEL: sel_neg1_1_32: ; CHECK: # %bb.0: ; CHECK-NEXT: xorl %eax, %eax ; CHECK-NEXT: cmpl $43, %edi ; CHECK-NEXT: setl %al ; CHECK-NEXT: leal -7(%rax,%rax,8), %eax ; CHECK-NEXT: retq %cmp = icmp sgt i32 %x, 42 %sel = select i1 %cmp, i32 -7, i32 2 ret i32 %sel } ; If the constants differ by a large power-of-2, that can be a shift of the difference plus the smaller constant. ; select Cond, C1, C2 --> add (mul (zext Cond), C1-C2), C2 define i8 @select_pow2_diff(i1 zeroext %cond) { ; CHECK-LABEL: select_pow2_diff: ; CHECK: # %bb.0: ; CHECK-NEXT: shlb $4, %dil ; CHECK-NEXT: orb $3, %dil ; CHECK-NEXT: movl %edi, %eax ; CHECK-NEXT: retq %sel = select i1 %cond, i8 19, i8 3 ret i8 %sel } define i16 @select_pow2_diff_invert(i1 zeroext %cond) { ; CHECK-LABEL: select_pow2_diff_invert: ; CHECK: # %bb.0: ; CHECK-NEXT: xorb $1, %dil ; CHECK-NEXT: movzbl %dil, %eax ; CHECK-NEXT: shll $6, %eax ; CHECK-NEXT: orl $7, %eax ; CHECK-NEXT: # kill: def %ax killed %ax killed %eax ; CHECK-NEXT: retq %sel = select i1 %cond, i16 7, i16 71 ret i16 %sel } define i32 @select_pow2_diff_neg(i1 zeroext %cond) { ; CHECK-LABEL: select_pow2_diff_neg: ; CHECK: # %bb.0: ; CHECK-NEXT: shlb $4, %dil ; CHECK-NEXT: movzbl %dil, %eax ; CHECK-NEXT: orl $-25, %eax ; CHECK-NEXT: retq %sel = select i1 %cond, i32 -9, i32 -25 ret i32 %sel } define i64 @select_pow2_diff_neg_invert(i1 zeroext %cond) { ; CHECK-LABEL: select_pow2_diff_neg_invert: ; CHECK: # %bb.0: ; CHECK-NEXT: xorb $1, %dil ; CHECK-NEXT: movzbl %dil, %eax ; CHECK-NEXT: shlq $7, %rax ; CHECK-NEXT: addq $-99, %rax ; CHECK-NEXT: retq %sel = select i1 %cond, i64 -99, i64 29 ret i64 %sel } ; This doesn't need a branch, but don't do the wrong thing if subtraction of the constants overflows. define i8 @sel_67_neg125(i32 %x) { ; CHECK-LABEL: sel_67_neg125: ; CHECK: # %bb.0: ; CHECK-NEXT: cmpl $42, %edi ; CHECK-NEXT: movb $67, %al ; CHECK-NEXT: jg .LBB31_2 ; CHECK-NEXT: # %bb.1: ; CHECK-NEXT: movb $-125, %al ; CHECK-NEXT: .LBB31_2: ; CHECK-NEXT: retq %cmp = icmp sgt i32 %x, 42 %sel = select i1 %cmp, i8 67, i8 -125 ret i8 %sel } ; In general, select of 2 constants could be: ; select Cond, C1, C2 --> add (mul (zext Cond), C1-C2), C2 --> add (and (sext Cond), C1-C2), C2 define i32 @select_C1_C2(i1 %cond) { ; CHECK-LABEL: select_C1_C2: ; CHECK: # %bb.0: ; CHECK-NEXT: testb $1, %dil ; CHECK-NEXT: movl $421, %ecx # imm = 0x1A5 ; CHECK-NEXT: movl $42, %eax ; CHECK-NEXT: cmovnel %ecx, %eax ; CHECK-NEXT: retq %sel = select i1 %cond, i32 421, i32 42 ret i32 %sel } define i32 @select_C1_C2_zeroext(i1 zeroext %cond) { ; CHECK-LABEL: select_C1_C2_zeroext: ; CHECK: # %bb.0: ; CHECK-NEXT: testl %edi, %edi ; CHECK-NEXT: movl $421, %ecx # imm = 0x1A5 ; CHECK-NEXT: movl $42, %eax ; CHECK-NEXT: cmovnel %ecx, %eax ; CHECK-NEXT: retq %sel = select i1 %cond, i32 421, i32 42 ret i32 %sel } define i32 @select_C1_C2_signext(i1 signext %cond) { ; CHECK-LABEL: select_C1_C2_signext: ; CHECK: # %bb.0: ; CHECK-NEXT: testb $1, %dil ; CHECK-NEXT: movl $421, %ecx # imm = 0x1A5 ; CHECK-NEXT: movl $42, %eax ; CHECK-NEXT: cmovnel %ecx, %eax ; CHECK-NEXT: retq %sel = select i1 %cond, i32 421, i32 42 ret i32 %sel } ; select (x == 2), 2, (x + 1) --> select (x == 2), x, (x + 1) define i64 @select_2_or_inc(i64 %x) { ; CHECK-LABEL: select_2_or_inc: ; CHECK: # %bb.0: ; CHECK-NEXT: leaq 1(%rdi), %rax ; CHECK-NEXT: cmpq $2, %rdi ; CHECK-NEXT: cmoveq %rdi, %rax ; CHECK-NEXT: retq %cmp = icmp eq i64 %x, 2 %add = add i64 %x, 1 %retval.0 = select i1 %cmp, i64 2, i64 %add ret i64 %retval.0 } define <4 x i32> @sel_constants_add_constant_vec(i1 %cond) { ; CHECK-LABEL: sel_constants_add_constant_vec: ; CHECK: # %bb.0: ; CHECK-NEXT: testb $1, %dil ; CHECK-NEXT: jne .LBB36_1 ; CHECK-NEXT: # %bb.2: ; CHECK-NEXT: movaps {{.*#+}} xmm0 = [12,13,14,15] ; CHECK-NEXT: retq ; CHECK-NEXT: .LBB36_1: ; CHECK-NEXT: movaps {{.*#+}} xmm0 = [4294967293,14,4,4] ; CHECK-NEXT: retq %sel = select i1 %cond, <4 x i32> , <4 x i32> %bo = add <4 x i32> %sel, ret <4 x i32> %bo } define <2 x double> @sel_constants_fmul_constant_vec(i1 %cond) { ; CHECK-LABEL: sel_constants_fmul_constant_vec: ; CHECK: # %bb.0: ; CHECK-NEXT: testb $1, %dil ; CHECK-NEXT: jne .LBB37_1 ; CHECK-NEXT: # %bb.2: ; CHECK-NEXT: movaps {{.*#+}} xmm0 = [1.188300e+02,3.454000e+01] ; CHECK-NEXT: retq ; CHECK-NEXT: .LBB37_1: ; CHECK-NEXT: movaps {{.*#+}} xmm0 = [-2.040000e+01,3.768000e+01] ; CHECK-NEXT: retq %sel = select i1 %cond, <2 x double> , <2 x double> %bo = fmul <2 x double> %sel, ret <2 x double> %bo } ; 4294967297 = 0x100000001. ; This becomes an opaque constant via ConstantHoisting, so we don't fold it into the select. define i64 @opaque_constant(i1 %cond, i64 %x) { ; CHECK-LABEL: opaque_constant: ; CHECK: # %bb.0: ; CHECK-NEXT: testb $1, %dil ; CHECK-NEXT: movl $23, %ecx ; CHECK-NEXT: movq $-4, %rax ; CHECK-NEXT: cmoveq %rcx, %rax ; CHECK-NEXT: movabsq $4294967297, %rcx # imm = 0x100000001 ; CHECK-NEXT: andq %rcx, %rax ; CHECK-NEXT: xorl %edx, %edx ; CHECK-NEXT: cmpq %rcx, %rsi ; CHECK-NEXT: sete %dl ; CHECK-NEXT: subq %rdx, %rax ; CHECK-NEXT: retq %sel = select i1 %cond, i64 -4, i64 23 %bo = and i64 %sel, 4294967297 %cmp = icmp eq i64 %x, 4294967297 %sext = sext i1 %cmp to i64 %add = add i64 %bo, %sext ret i64 %add }