Fix arc assumption that insns are not re-recognized

Testing the V2 version of Manolis's fold-mem-offsets patch exposed a minor bug
in the arc backend.

The movsf_insn pattern has constraints which allow storing certain constants
to memory.  reload/lra will target those alternatives under the right
circumstances.  However the insn's condition requires that one of the two
operands must be a register.

Thus if a pass were to force re-recognition of the pattern we can get an
unrecognized insn failure.

This patch adjusts the conditions to more closely match movsi_insn.  More
specifically it allows storing a constant into a limited set of memory
operands (as defined by the Usc constraint).  movqi_insn has the same
core problem and gets the same solution.

Committed after the tester validated there are not regresisons

gcc/
	* config/arc/arc.md (movqi_insn): Allow certain constants to
	be stored into memory in the pattern's condition.
	(movsf_insn): Similarly.

diff --git a/gcc/config/arc/arc.md b/gcc/config/arc/arc.md
index c51ce1733501c2a5fbce829b39811dc17734c4b6..1f122d9507f27ce8bdc88aaaeb5fc74604e860ea 100644 (file)
--- a/gcc/config/arc/arc.md
+++ b/gcc/config/arc/arc.md
@@ -705,6 +705,9 @@ archs4x, archs4xd"
        (match_operand:QI 1 "move_src_operand"  "rL,rP,q,P,hCm1,cL, I,?Rac,i,?i,T,q,Usd,Ucm,m,?Rac,c,?Rac,Cm3,i"))]
   "register_operand (operands[0], QImode)
    || register_operand (operands[1], QImode)
+   || (CONSTANT_P (operands[1])
+       && (!satisfies_constraint_I (operands[1]) || !optimize_size)
+       && satisfies_constraint_Usc (operands[0]))
    || (satisfies_constraint_Cm3 (operands[1])
        && memory_operand (operands[0], QImode))"
   "@
@@ -1363,7 +1366,10 @@ archs4x, archs4xd"
   [(set (match_operand:SF 0 "move_dest_operand"   "=h,h,   r,r,  q,S,Usc,r,m")
        (match_operand:SF 1 "move_src_operand"  "hCfZ,E,rCfZ,E,Uts,q,  E,m,r"))]
   "register_operand (operands[0], SFmode)
-   || register_operand (operands[1], SFmode)"
+   || register_operand (operands[1], SFmode)
+   || (CONSTANT_P (operands[1])
+       && (!satisfies_constraint_I (operands[1]) || !optimize_size)
+       && satisfies_constraint_Usc (operands[0]))"
   "@
    mov%?\\t%0,%1
    mov%?\\t%0,%1 ; %A1