[PATCH] D24607: [mips] seq macro support

[Simon Dardis via llvm-commits]

sdardis marked an inline comment as done.
sdardis added inline comments.


================
Comment at: lib/Target/Mips/AsmParser/MipsAsmParser.cpp:3862-3878
+  if (!isUInt<16>(Imm)) {
+    unsigned ATReg = getATReg(IDLoc);
+    if (!ATReg)
+      return true;
+
+    if (Imm < 0) {
+      Imm = -Imm;
----------------
vkalintiris wrote:
> The constants manipulation here looks problematic, eg:
> 
>   seq     $4, $5, -66666
> 
> With gas:
> 
>   lui     at,0xfffe
>   ori     at,at,0xfb96
>   xor     a0,a1,at
>   sltiu   a0,a0,1
> 
> With llvm-mc:
> 
>   addiu   $4, $5, 1130
>   sltiu   $4, $4, 1
> 
> Similarly for:
> 
>   seq     $4, $5, -2147483648
> 
> gas:
> 
>   lui     at,0x8000
>   xor     a0,a1,at 
>   sltiu   a0,a0,1
> 
> llvm-mc:
> 
>   addiu   $4, $5, 0
>   sltiu   $4, $4, 1
> 
> Also, on 64-bit we should generate a daddiu instead of an addiu according to the gas testsuite in binutils.
Right. It appears that seqi reads immediates like li does. I have a working copy with this addressed and I'll add your examples to the test.


https://reviews.llvm.org/D24607