[Bug middle-end/44852] [4.6 Regression]: miscompilation (of e.g. newlib dtoa.c) after mem-ref2 merge

[rguenth at gcc dot gnu dot org]

------- Comment #6 from rguenth at gcc dot gnu dot org  2010-07-08 21:57 -------
The issue seems to be the uncprop tree pass which does

@@ -32,7 +32,7 @@

 <bb 6>:
   # s_18 = PHI <s_1(4), s_1(5)>
-  # D.1967_19 = PHI <57(4), D.1967_4(5)>
+  # D.1967_19 = PHI <D.1967_4(4), D.1967_4(5)>
   D.1968_7 = D.1967_19 + 1;
   MEM[(char *)s_18 + -1B] = D.1968_7;
   return s_18;

where D.1967_4 is defined as D.1967_4 = MEM[(char *)s_1 + -1B];

and in BB4 we define that location to MEM[(char *)s_14 + -1B] = 48;


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44852