[llvm-commits] [llvm] r109693 - /llvm/trunk/lib/Target/ARM/ARMInstrThumb2.td

[Jim Grosbach]

Author: grosbach
Date: Wed Jul 28 18:17:45 2010
New Revision: 109693

URL: http://llvm.org/viewvc/llvm-project?rev=109693&view=rev
Log:
Remove incorrect substitution pattern for UXTB16. It wrongly assumed the input shift was actually a rotate. rdar://8240138

Modified:
    llvm/trunk/lib/Target/ARM/ARMInstrThumb2.td

Modified: llvm/trunk/lib/Target/ARM/ARMInstrThumb2.td
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/ARMInstrThumb2.td?rev=109693&r1=109692&r2=109693&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/ARMInstrThumb2.td (original)
+++ llvm/trunk/lib/Target/ARM/ARMInstrThumb2.td Wed Jul 28 18:17:45 2010
@@ -1352,8 +1352,12 @@
 defm t2UXTB16 : T2I_unary_rrot_uxtb16<0b011, "uxtb16",
                                UnOpFrag<(and node:$Src, 0x00FF00FF)>>;
 
-def : T2Pat<(and (shl GPR:$Src, (i32 8)), 0xFF00FF),
-            (t2UXTB16r_rot GPR:$Src, 24)>, Requires<[HasT2ExtractPack]>;
+// FIXME: This pattern incorrectly assumes the shl operator is a rotate.
+//        The transformation should probably be done as a combiner action
+//        instead so we can include a check for masking back in the upper
+//        eight bits of the source into the lower eight bits of the result.
+//def : T2Pat<(and (shl GPR:$Src, (i32 8)), 0xFF00FF),
+//            (t2UXTB16r_rot GPR:$Src, 24)>, Requires<[HasT2ExtractPack]>;
 def : T2Pat<(and (srl GPR:$Src, (i32 8)), 0xFF00FF),
             (t2UXTB16r_rot GPR:$Src, 8)>, Requires<[HasT2ExtractPack]>;