[PATCH] D142535: [DAGCombine] Fold redundant select

[Asmaa via Phabricator via llvm-commits]

asmok-g added a comment.

Thank you for reverting and sorry for late reply.
In case it was still needed, here's a repro for the miscompile:

  #include <stdint.h>
  typedef enum {
    G_UNICODE_BREAK_ZERO_WIDTH_SPACE,
    G_UNICODE_BREAK_ALPHABETIC,
    G_UNICODE_BREAK_NEXT_LINE,
    G_UNICODE_BREAK_WORD_JOINER
  } GUnicodeBreakType;
  int8_t break_property_data[][1]{G_UNICODE_BREAK_ALPHABETIC};
  typedef enum { BREAK_PROHIBITED, BREAK_ALLOWED } BreakOpportunity;
  char utf8_skip_data[]{};
  char *g_utf8_skip = utf8_skip_data;
  #define g_utf8_next_char(p) p + g_utf8_skip[*p]
  #define TPROP_PART1(Page, Char) break_property_data[Page][Char]
  #define PROP(Char) (5 ? TPROP_PART1(0, Char) : 0)
  GUnicodeBreakType g_unichar_break_type(int c) {
    return (GUnicodeBreakType)PROP(c);
  }
  struct _PangoLogAttr {
    unsigned is_line_break;
  };
  int pango_default_break_i, pango_default_break_done;
  GUnicodeBreakType pango_default_break_prev_break_type;
  void pango_default_break(char *text, _PangoLogAttr *attrs) {
    char *next;
    uint32_t next_wc, almost_done;
    GUnicodeBreakType next_break_type;
    next = text;
    for (; !pango_default_break_done; pango_default_break_i++) {
      BreakOpportunity break_op;
      if (almost_done)
        pango_default_break_done = !0;
      next = g_utf8_next_char(next);
      if (*next)
        almost_done = next_break_type = g_unichar_break_type(next_wc);
      attrs[pango_default_break_i].is_line_break = !0;
      if (pango_default_break_prev_break_type == G_UNICODE_BREAK_WORD_JOINER ||
          next_break_type == G_UNICODE_BREAK_WORD_JOINER)
        break_op = BREAK_PROHIBITED;
      if (pango_default_break_prev_break_type)
        break_op = BREAK_PROHIBITED;
      if (pango_default_break_prev_break_type == G_UNICODE_BREAK_NEXT_LINE)
        break_op = BREAK_ALLOWED;
      switch (break_op)
      case BREAK_PROHIBITED:
        attrs[pango_default_break_i].is_line_break = 0;
      pango_default_break_prev_break_type = next_break_type;
    }
  }
  int main() {
    _PangoLogAttr logs[7];
    pango_default_break("ગોંડલનું મોવિયા અને દેરડીકુંભાજી ગામ સજ્જડ બંધ", &logs[0]);
    int ret = logs[1].is_line_break << 1;
    return ret;
  }

reproducing command is

  $ clang -O1 -fsanitize=address break.cc -o break

returns 0 before patch and 2 after.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D142535/new/

https://reviews.llvm.org/D142535