[LLVMbugs] [Bug 12880] New: static constructor not simplified

[bugzilla-daemon at llvm.org]

http://llvm.org/bugs/show_bug.cgi?id=12880

             Bug #: 12880
           Summary: static constructor not simplified
           Product: libraries
           Version: trunk
          Platform: PC
        OS/Version: Linux
            Status: NEW
          Severity: enhancement
          Priority: P
         Component: Interprocedural Optimizations
        AssignedTo: unassignedbugs at nondot.org
        ReportedBy: rafael.espindola at gmail.com
                CC: llvmbugs at cs.uiuc.edu
    Classification: Unclassified


We compile


void foo();
struct bar {
  bar() : zed(0) {
  }
  unsigned zed;
};
bar bah;
struct baz {
  baz() {
    foo();
  }
};
static baz bax;

to

%struct.bar = type { i32 }
@bah = global %struct.bar zeroinitializer, align 4
@llvm.global_ctors = appending global [1 x { i32, void ()* }] [{ i32, void ()*
} { i32 65535, void ()* @_GLOBAL__I_a }]
declare void @_Z3foov() optsize
define internal void @_GLOBAL__I_a() nounwind section ".text.startup" {
entry:
  store i32 0, i32* getelementptr inbounds (%struct.bar* @bah, i64 0, i32 0),
align 4
  tail call void @_Z3foov() nounwind optsize
  ret void
}

Note that the store of 0 is unnecessary. In fact, if the call to foo is
commented out we produce

%struct.bar = type { i32 }
@bah = global %struct.bar zeroinitializer, align 4
@llvm.global_ctors = appending global [0 x { i32, void ()* }] zeroinitializer

-- 
Configure bugmail: http://llvm.org/bugs/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are on the CC list for the bug.