[llvm-commits] [llvm] r118362 - in /llvm/trunk: lib/Target/X86/X86InstrInfo.td test/MC/X86/x86-64.s

[Chris Lattner]

Author: lattner
Date: Sat Nov  6 17:35:34 2010
New Revision: 118362

URL: http://llvm.org/viewvc/llvm-project?rev=118362&view=rev
Log:
add aliases for movs between seg registers and mem.  There are multiple
different forms of this instruction (movw/movl/movq) which we reported
as being ambiguous.  Since they all do the same thing, gas just picks the
one with the shortest encoding.  Follow its lead here.

This implements rdar://8208615

Modified:
    llvm/trunk/lib/Target/X86/X86InstrInfo.td
    llvm/trunk/test/MC/X86/x86-64.s

Modified: llvm/trunk/lib/Target/X86/X86InstrInfo.td
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86InstrInfo.td?rev=118362&r1=118361&r2=118362&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86InstrInfo.td (original)
+++ llvm/trunk/lib/Target/X86/X86InstrInfo.td Sat Nov  6 17:35:34 2010
@@ -1465,6 +1465,11 @@
 def : InstAlias<"calll $seg, $off", (FARCALL32i i32imm:$off, i16imm:$seg)>;
 def : InstAlias<"jmpl $seg, $off",  (FARJMP32i  i32imm:$off, i16imm:$seg)>;
 
+// Force mov without a suffix with a segment and mem to prefer the 'l' form of
+// the move.  All segment/mem forms are equivalent, this has the shortest
+// encoding.
+def : InstAlias<"mov $mem, $seg", (MOV32sm SEGMENT_REG:$seg, i32mem:$mem)>;
+def : InstAlias<"mov $seg, $mem", (MOV32ms i32mem:$mem, SEGMENT_REG:$seg)>;
 
 // Match 'movq <largeimm>, <reg>' as an alias for movabsq.
 def : InstAlias<"movq $imm, $reg", (MOV64ri GR64:$reg, i64imm:$imm)>;

Modified: llvm/trunk/test/MC/X86/x86-64.s
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/X86/x86-64.s?rev=118362&r1=118361&r2=118362&view=diff
==============================================================================
--- llvm/trunk/test/MC/X86/x86-64.s (original)
+++ llvm/trunk/test/MC/X86/x86-64.s Sat Nov  6 17:35:34 2010
@@ -873,3 +873,10 @@
 // CHECK: sidt	4(%rax)
 // CHECK:  encoding: [0x0f,0x01,0x48,0x04]
         	sidtq	4(%rax)
+
+
+// rdar://8208615
+mov (%rsi), %gs  // CHECK: movl	(%rsi), %gs # encoding: [0x8e,0x2e]
+mov %gs, (%rsi)  // CHECK: movl	%gs, (%rsi) # encoding: [0x8c,0x2e]
+
+