[AMDGPU] Recognize x & (-1 >> (32 - y)) pattern.
Summary:
D47980 will canonicalize the `x << (32 - y) >> (32 - y)`,
which is the pattern the AMDGPU expects to `x & (-1 >> (32 - y))`,
which is not recognized by AMDGPU.
Thus, it needs to be recognized, too.
Reviewers: nhaehnle, bogner, tstellar, arsenm
Reviewed By: arsenm
Subscribers: arsenm, kzhuravl, wdng, yaxunl, dstuttard, tpr, t-tye, llvm-commits
Tags: #amdgpu
Differential Revision: https://reviews.llvm.org/D48007
llvm-svn: 334815
diff --git a/llvm/lib/Target/AMDGPU/AMDGPUInstructions.td b/llvm/lib/Target/AMDGPU/AMDGPUInstructions.td
index 4d7da21..22a7a9c 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUInstructions.td
+++ b/llvm/lib/Target/AMDGPU/AMDGPUInstructions.td
@@ -682,6 +682,13 @@
(UBFE $src, $rshift, (MOV (i32 (IMMPopCount $mask))))
>;
+ // x & (-1 >> (bitwidth - y))
+ def : AMDGPUPat <
+ (and i32:$src, (srl_oneuse -1, (sub 32, i32:$width))),
+ (UBFE $src, (i32 0), $width)
+ >;
+
+ // x << (bitwidth - y) >> (bitwidth - y)
def : AMDGPUPat <
(srl (shl_oneuse i32:$src, (sub 32, i32:$width)), (sub 32, i32:$width)),
(UBFE $src, (i32 0), $width)