changed 'uses REG=%1' behaviour: if no REG containing %1 is found, an

attempt is made to find an empty one

diff --git a/mach/proto/ncg/codegen.c b/mach/proto/ncg/codegen.c
index ff02718..cffb11a 100644 (file)
--- a/mach/proto/ncg/codegen.c
+++ b/mach/proto/ncg/codegen.c
@@ -563,7 +563,7 @@ normalfailed:       if (stackpad!=tokpatlen) {
        int npos,npos2,pos[NREGS],pos2[NREGS];
        unsigned mincost,t;
        struct reginfo *rp,**rpp;
-       token_t token,mtoken,token2;
+       token_t token,token2;
        int propno;
        int exactmatch;
        int decision;
@@ -585,7 +585,7 @@ normalfailed:       if (stackpad!=tokpatlen) {
                                if (getrefcount(rp-machregs, FALSE)==0) {
                                        pos[npos++] = rp-machregs;
                                        if (eqtoken(&rp->r_contents,&token))
-                                               exactmatch++;
+                                               pos2[exactmatch++] = rp-machregs;
                                }
                        /*
                         * Now pos[] contains all free registers with desired
@@ -606,6 +606,21 @@ normalfailed:      if (stackpad!=tokpatlen) {
                                CHKCOST();
                        }
                } while (npos==0);
+
+               if (!exactmatch && tinstno!=0) {
+                       /*
+                        * No exact match, but we were looking for a particular
+                        * token. Now try to find registers of which no
+                        * known contents is available (the others might still
+                        * be useful).
+                        */
+                       instance(0,&token2);
+                       for (i=0;i<npos;i++)
+                               if (eqtoken(&machregs[pos[i]].r_contents,&token2)) {
+                                       pos2[exactmatch++] = pos[i];
+                               }
+               }
+
                if (!exactmatch) {
                        npos2=npos;
                        for(i=0;i<npos;i++)
@@ -616,17 +631,15 @@ normalfailed:     if (stackpad!=tokpatlen) {
                         * We take only one equally likely register out of every
                         * equivalence class as given by set of properties.
                         */
-                       mtoken = token;
                        npos2=0;
-                       for(i=0;i<npos;i++)
-                               if (eqtoken(&machregs[pos[i]].r_contents,&mtoken)) {
-                                       pos2[npos2++] = pos[i];
-                                       for(j=0;j<npos2-1;j++)
-                                               if (eqregclass(pos2[j],pos[i])) {
-                                                       npos2--;
-                                                       break;
-                                               }
-                               }
+                       for(i=0;i<exactmatch;i++) {
+                               pos2[npos2++] = pos2[i];
+                               for(j=0;j<npos2-1;j++)
+                                       if (eqregclass(pos2[j],pos2[i])) {
+                                               npos2--;
+                                               break;
+                                       }
+                       }
                }
                /*
                 * Now pos2[] contains all possibilities to try, if more than