[PATCH] D55570: [AMDGPU] Improve SDWA generation for V_OR_B32_E32.

Thu Dec 13 05:07:08 PST 2018

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

================
Comment at: lib/Target/AMDGPU/SIPeepholeSDWA.cpp:707
+      Msk = WORD_0;
+    else if (*Imm == 0x0ffff0000 || *Imm == -65536)
+      Msk = WORD_1;
----------------
arsenm wrote:
> These are the same thing
actually, these are not always the same in the LLVM IR for Immediate constants, when i dump out the Imm value one can see

This is from sdwa-ors.mir
IMM 4294901760
ffff0000

and this is from load-log16.ll
IMM -65536
ffffffffffff0000

it would probably be easier to simply preserve the low 32 bits of the Imm which would allow me to get rid of the 2 additional expressions
|| *Imm == -65536
and
|| *Imm == -16777216

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D55570/new/

https://reviews.llvm.org/D55570