fix instruction matching errors in i386 CFI generation

fdiv and fmul instructions were wrongly matched by the rules for
integer div and mul instructions, leading to incorrect conclusions
about register values being clobbered.

tools/add-cfi.i386.awk

@@ -188,9 +188,9 @@ function trashed(register) {
 /(add|addl|sub|subl|and|or|xor|lea|sal|sar|shl|shr) %e(ax|bx|cx|dx|si|di|bp),/ {
   trashed(get_reg1())
 }
-/i?mul [^,]*$/                    { trashed("eax"); trashed("edx") }
-/i?mul %e(ax|bx|cx|dx|si|di|bp),/ { trashed(get_reg1()) }
-/i?div/                           { trashed("eax"); trashed("edx") }
+/^i?mul [^,]*$/                    { trashed("eax"); trashed("edx") }
+/^i?mul %e(ax|bx|cx|dx|si|di|bp),/ { trashed(get_reg1()) }
+/^i?div/                           { trashed("eax"); trashed("edx") }
 /(dec|inc|not|neg|pop) %e(ax|bx|cx|dx|si|di|bp)/  { trashed(get_reg()) }
 /cpuid/ { trashed("eax"); trashed("ebx"); trashed("ecx"); trashed("edx") }