[LLVMdev] Vector comparisons

[Gordon Henriksen]

Are the ICMP and FCMP instructions meant to accept vectors operands  
or no? Verifier excludes vectors, as does the AsmParser[1]. But the  
CmpInst constructor accepts vectors[2], and they are documented as  
allowed:

> If the operands [of icmp or fcmp] are packed typed, the elements of  
> the vector are compared in turn and the predicate must hold for all  
> elements.

— Gordon


[1]
% llvm-as <<'EOT' >/dev/null
define i1 %cmpvint(<4 x i32> %x, <4 x i32> %y) {
   %res = icmp eq <4 x i32> %y, %y
   ret %res
}
EOT
llvm-as: <stdin>:2,0: Packed types not supported by icmp instruction
% llvm-as <<'EOT' >/dev/null
define i1 %cmpfint(<4 x float> %x, <4 x float> %y) {
   %res = fcmp oeq <4 x float> %y, %y
   ret %res
}
EOT
llvm-as: <stdin>:2,0: Packed types not supported by fcmp instruction


[2] From CmpInst::CmpInst:

     // Check that the operands are the right type
     assert(Op0Ty->isInteger() || isa<PointerType>(Op0Ty) ||
            (isa<PackedType>(Op0Ty) &&
             cast<PackedType>(Op0Ty)->getElementType()->isInteger()) &&
            "Invalid operand types for ICmp instruction");
...
   // Check that the operands are the right type
   assert(Op0Ty->isFloatingPoint() || (isa<PackedType>(Op0Ty) &&
          cast<PackedType>(Op0Ty)->getElementType()->isFloatingPoint 
()) &&
          "Invalid operand types for FCmp instruction");

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