[LLVMbugs] [Bug 1296] NEW: poor codegen for code size

[bugzilla-daemon at cs.uiuc.edu]

http://llvm.org/bugs/show_bug.cgi?id=1296

           Summary: poor codegen for code size
           Product: libraries
           Version: 1.0
          Platform: All
        OS/Version: All
            Status: NEW
          Severity: normal
          Priority: P2
         Component: Common Code Generator Code
        AssignedTo: unassignedbugs at nondot.org
        ReportedBy: sabre at nondot.org


This contrived testcase:

int foo(int A, int B, int C) {
  int i;
  int result = 0;

  if (A == 1)  {
    for (i = 0; i < 1000; ++i) {
      if (i & B) {result = 1; break; }
    }
  } else if (A == 0) {
    for (i = 0; i < 1000; ++i) {
      if (i & C) {result = 1; break; }
   }
  } else if (A == 2) {
    for (i = 0; i < 1000; ++i) {
      if (i & C) {result = 1; break; }
    }
  }

out:
  return result;
}

Produces silly code like this:

LBB1_19:        #bb13.out.loopexit1_crit_edge
        movl $1, %eax
        jmp LBB1_15     #out
LBB1_20:        #bb.out.loopexit_crit_edge
        movl $1, %eax
        jmp LBB1_15     #out
LBB1_21:        #bb27.out.loopexit3_crit_edge
        movl $1, %eax
        jmp LBB1_15     #out



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