[X86] Add additional tests for folding `(select (setgt X, -1), C, C+1)`; NFC

[goldstein.w.n]

Summary

The goal of these tests is to hit more cases where typeof(X) != typeof(C).

[goldstein.w.n]

Rebase

[RKSimon]

i64 test cases (both a compare and select) would be useful to see what happens on 32-bit builds

[goldstein.w.n]

In D145001#4164267, @RKSimon wrote:

i64 test cases (both a compare and select) would be useful to see what happens on 32-bit builds

We already have an i64 test in the file (the original test case that prompted this patch).
See: selecti64i32

[goldstein.w.n]

Add tests for sext + add case, add comment explaining missing i64 case

[goldstein.w.n]

In D145001#4165297, @goldstein.w.n wrote:

In D145001#4164267, @RKSimon wrote:

i64 test cases (both a compare and select) would be useful to see what happens on 32-bit builds

We already have an i64 test in the file (the original test case that prompted this patch).
See: selecti64i32

Added comment this affect.

[RKSimon]

LGTM - cheers

llvm/test/CodeGen/X86/select-constant-xor.ll

47

found it!

68

found it!

258

Cheers - instead of temporarily altering your patch like this you can just add a comment in phab to any line in the file

[goldstein.w.n]

Rebase

[goldstein.w.n]

Rebase

llvm/test/CodeGen/X86/select-constant-xor.ll

 ; X64-NEXT:    sarq $63, %rax
 ; X64-NEXT:    xorq $2147483647, %rax # imm = 0x7FFFFFFF
 ; X64-NEXT:    retq
   %c = icmp sgt i64 %a, -1
   %s = select i1 %c, i64 2147483647, i64 -2147483648
   ret i64 %s
 }
 
 define i32 @selecti64i32(i64 %a) {
 ; X86-LABEL: selecti64i32:
 ; X86:       # %bb.0:
 ; X86-NEXT:    xorl %eax, %eax
 ; X86-NEXT:    cmpl $0, {{[0-9]+}}(%esp)
 ; X86-NEXT:    sets %al
 ; X86-NEXT:    addl $2147483647, %eax # imm = 0x7FFFFFFF
 ; X86-NEXT:    retl
 ;
 ; X64-LABEL: selecti64i32:
 ; X64:       # %bb.0:
 ; X64-NEXT:    xorl %eax, %eax
 ; X64-NEXT:    testq %rdi, %rdi
 ; X64-NEXT:    sets %al
 ; X64-NEXT:    addl $2147483647, %eax # imm = 0x7FFFFFFF
 ; X64-NEXT:    retq
   %c = icmp sgt i64 %a, -1
   %s = select i1 %c, i32 2147483647, i32 -2147483648
   ret i32 %s
 }
 
 define i64 @selecti32i64(i32 %a) {
 ; X86-LABEL: selecti32i64:
 ; X86:       # %bb.0:
 ; X86-NEXT:    movl {{[0-9]+}}(%esp), %edx
 ; X86-NEXT:    sarl $31, %edx
 ; X86-NEXT:    movl %edx, %eax
 ; X86-NEXT:    xorl $2147483647, %eax # imm = 0x7FFFFFFF
 ; X86-NEXT:    retl
 ;

 ; X64-NEXT:    addl %esi, %eax
 ; X64-NEXT:    retq
   %c = icmp sle i32 %a, -1
   %s = select i1 %c, i32 -128, i32 127
   %s2 = select i1 %c, i32 %d, i32 %b
   %x = add i32 %s, %s2
   ret i32 %x
 }
+
+; we already have a test for the i64 case at `selecti64i32`.
+define i32 @selecti16i32_offby1(i16 %a) {
+; X86-LABEL: selecti16i32_offby1:
+; X86:       # %bb.0:
+; X86-NEXT:    xorl %eax, %eax
+; X86-NEXT:    cmpw $0, {{[0-9]+}}(%esp)
+; X86-NEXT:    sets %al
+; X86-NEXT:    addl $2147483647, %eax # imm = 0x7FFFFFFF
+; X86-NEXT:    retl
+;
+; X64-LABEL: selecti16i32_offby1:
+; X64:       # %bb.0:
+; X64-NEXT:    xorl %eax, %eax
+; X64-NEXT:    testw %di, %di
+; X64-NEXT:    sets %al
+; X64-NEXT:    addl $2147483647, %eax # imm = 0x7FFFFFFF
+; X64-NEXT:    retq
+  %c = icmp sgt i16 %a, -1
+  %s = select i1 %c, i32 2147483647, i32 -2147483648
+  ret i32 %s
+}
+
+define i32 @selecti8i32_offby1(i8 %a) {
+; X86-LABEL: selecti8i32_offby1:
+; X86:       # %bb.0:
+; X86-NEXT:    xorl %eax, %eax
+; X86-NEXT:    cmpb $0, {{[0-9]+}}(%esp)
+; X86-NEXT:    sets %al
+; X86-NEXT:    addl $2147483647, %eax # imm = 0x7FFFFFFF
+; X86-NEXT:    retl
+;
+; X64-LABEL: selecti8i32_offby1:
+; X64:       # %bb.0:
+; X64-NEXT:    xorl %eax, %eax
+; X64-NEXT:    testb %dil, %dil
+; X64-NEXT:    sets %al
+; X64-NEXT:    addl $2147483647, %eax # imm = 0x7FFFFFFF
+; X64-NEXT:    retq
+  %c = icmp sgt i8 %a, -1
+  %s = select i1 %c, i32 2147483647, i32 -2147483648
+  ret i32 %s
+}
+
+
+define i32 @selecti64i32_offby1_add(i64 %a) {
+; X86-LABEL: selecti64i32_offby1_add:
+; X86:       # %bb.0:
+; X86-NEXT:    xorl %eax, %eax
+; X86-NEXT:    cmpl $0, {{[0-9]+}}(%esp)
+; X86-NEXT:    setns %al
+; X86-NEXT:    addl $2147483647, %eax # imm = 0x7FFFFFFF
+; X86-NEXT:    retl
+;
+; X64-LABEL: selecti64i32_offby1_add:
+; X64:       # %bb.0:
+; X64-NEXT:    xorl %eax, %eax
+; X64-NEXT:    testq %rdi, %rdi
+; X64-NEXT:    setns %al
+; X64-NEXT:    addl $2147483647, %eax # imm = 0x7FFFFFFF
+; X64-NEXT:    retq
+  %c = icmp sgt i64 %a, -1
+  %s = select i1 %c, i32 2147483648, i32 2147483647
+  ret i32 %s
+}
+
+define i32 @selecti16i32_offby1_add(i16 %a) {
+; X86-LABEL: selecti16i32_offby1_add:
+; X86:       # %bb.0:
+; X86-NEXT:    xorl %eax, %eax
+; X86-NEXT:    cmpw $0, {{[0-9]+}}(%esp)
+; X86-NEXT:    setns %al
+; X86-NEXT:    addl $2147483647, %eax # imm = 0x7FFFFFFF
+; X86-NEXT:    retl
+;
+; X64-LABEL: selecti16i32_offby1_add:
+; X64:       # %bb.0:
+; X64-NEXT:    xorl %eax, %eax
+; X64-NEXT:    testw %di, %di
+; X64-NEXT:    setns %al
+; X64-NEXT:    addl $2147483647, %eax # imm = 0x7FFFFFFF
+; X64-NEXT:    retq
+  %c = icmp sgt i16 %a, -1
+  %s = select i1 %c, i32 2147483648, i32 2147483647
+  ret i32 %s
+}
+
+define i32 @selecti8i32_offby1_add(i8 %a) {
+; X86-LABEL: selecti8i32_offby1_add:
+; X86:       # %bb.0:
+; X86-NEXT:    xorl %eax, %eax
+; X86-NEXT:    cmpb $0, {{[0-9]+}}(%esp)
+; X86-NEXT:    setns %al
+; X86-NEXT:    addl $2147483647, %eax # imm = 0x7FFFFFFF
+; X86-NEXT:    retl
+;
+; X64-LABEL: selecti8i32_offby1_add:
+; X64:       # %bb.0:
+; X64-NEXT:    xorl %eax, %eax
+; X64-NEXT:    testb %dil, %dil
+; X64-NEXT:    setns %al
+; X64-NEXT:    addl $2147483647, %eax # imm = 0x7FFFFFFF
+; X64-NEXT:    retq
+  %c = icmp sgt i8 %a, -1
+  %s = select i1 %c, i32 2147483648, i32 2147483647
+  ret i32 %s
+}
+
+
 ;; NOTE: These prefixes are unused and the list is autogenerated. Do not add tests below this line:
 ; X64-FASTINC: {{.*}}
 ; X64-SLOWINC: {{.*}}