Intel® oneAPI DPC++/C++ Compiler Developer Guide and Reference

ID 767253
Date 3/22/2024
Public

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Comparison Operators

The equality and inequality comparison operands can have mixed signedness, but they must be of the same size. The comparison operators for less-than and greater-than must be of the same sign and size. For example:

  • The nearest common ancestor is returned for compare for equal/not-equal operations:
    Iu8vec8 A;
    Is8vec8 B;
    I8vec8 C;
    
    C = cmpneq(A,B);
    
  • Type cast needed for different-sized elements for equal/not-equal comparisons:
    Iu8vec8 A, C;
    Is16vec4 B;
    
    C = cmpeq(A,(Iu8vec8)B);
    
  • Type cast needed for sign or size differences for less-than and greater-than comparisons:
    Iu16vec4 A;
    Is16vec4 B, C;
    
    C = cmpge((Is16vec4)A,B);
    C = cmpgt(B,C);
    

Inequality Comparison Symbols and Corresponding Intrinsics

Comparison

Operators

Syntax

Intrinsic

Equality

cmpeq

R = cmpeq(A, B)

_mm_cmpeq_pi32
_mm_cmpeq_pi16
_mm_cmpeq_pi8

Inequality

cmpneq

R = cmpneq(A, B)

_mm_cmpeq_pi32
_mm_cmpeq_pi16
_mm_cmpeq_pi8
_mm_andnot_si64

Greater Than

cmpgt

R = cmpgt(A, B)

_mm_cmpgt_pi32
_mm_cmpgt_pi16
_mm_cmpgt_pi8

Greater Than
or Equal To

cmpge

R = cmpge(A, B)

_mm_cmpgt_pi32
_mm_cmpgt_pi16
_mm_cmpgt_pi8
_mm_andnot_si64

Less Than

cmplt

R = cmplt(A, B)

_mm_cmpgt_pi32
_mm_cmpgt_pi16
_mm_cmpgt_pi8

Less Than
or Equal To

cmple

R = cmple(A, B)

_mm_cmpgt_pi32
_mm_cmpgt_pi16
_mm_cmpgt_pi8
_mm_andnot_si64

Compare Operator Overloading

Comparison operators have the restriction that the operands must be the size and sign as listed in the following table.

R

Comparison

Operand A

Operand B

I32vec2 R

cmpeq
cmpne

I[s|u]32vec2 B

I[s|u]32vec2 B

I16vec4 R

 

I[s|u]16vec4 B

I[s|u]16vec4 B

I8vec8 R

 

I[s|u]8vec8 B

I[s|u]8vec8 B

I32vec2 R

cmpgt
cmpge
cmplt
cmple

Is32vec2 B

Is32vec2 B

I16vec4 R

 

Is16vec4 B

Is16vec4 B

I8vec8 R

 

Is8vec8 B

Is8vec8 B