; 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: movzbl %dil, %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: andb $1, %dil ; CHECK-NEXT: movzbl %dil, %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: %EDI %EDI %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: movzbl %dil, %eax ; CHECK-NEXT: decl %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: andb $1, %dil ; CHECK-NEXT: movzbl %dil, %eax ; CHECK-NEXT: decl %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: movzbl %dil, %eax ; CHECK-NEXT: negl %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: movsbl %dil, %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: %EDI %EDI %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: movzbl %dil, %eax ; CHECK-NEXT: addl $41, %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: andb $1, %dil ; CHECK-NEXT: movzbl %dil, %eax ; CHECK-NEXT: addl $41, %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: andb $1, %dil ; CHECK-NEXT: cmpb $1, %dil ; CHECK-NEXT: movl $41, %eax ; CHECK-NEXT: adcl $0, %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: cmpb $1, %dil ; CHECK-NEXT: movl $41, %eax ; CHECK-NEXT: adcl $0, %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: andb $1, %dil ; CHECK-NEXT: cmpb $1, %dil ; CHECK-NEXT: movl $41, %eax ; CHECK-NEXT: adcl $0, %eax ; CHECK-NEXT: retq %sel = select i1 %cond, i32 41, i32 42 ret i32 %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: testb %dil, %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_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 }