[Bug rtl-optimization/19097] New: Lots of else ifs take forever to compile

[phython at gcc dot gnu dot org]

The following bit of code doesn't compile on my laptop (at -O2) because gcc gets
killed. This happens with gcc 3.3.5 and gcc 3.4.3 and gcc 4.0

#define CL0(a) else if (b == a) { f(); }
#define CL1(a) CL0(a##0) CL0(a##1) CL0(a##2) CL0(a##3) CL0(a##4) CL0(a##5) \
 CL0(a##6) CL0(a##7) CL0(a##8) CL0(a##9)
#define CL2(a) CL1(a##0) CL1(a##1) CL1(a##2) CL1(a##3) CL1(a##4) CL1(a##5) \
 CL1(a##6) CL1(a##7) CL1(a##8) CL1(a##9)
#define CL3(a) CL2(a##0) CL2(a##1) CL2(a##2) CL2(a##3) CL2(a##4) CL2(a##5) \
 CL2(a##6) CL2(a##7) CL2(a##8) CL2(a##9)
#define CL4(a) CL3(a##0) CL3(a##1) CL3(a##2) CL3(a##3) CL3(a##4) CL3(a##5) \
 CL3(a##6) CL3(a##7) CL3(a##8) CL3(a##9)
#define CL5(a) CL4(a##0) CL4(a##1) CL4(a##2) CL4(a##3) CL4(a##4) CL4(a##5) \
 CL4(a##6) CL4(a##7) CL4(a##8) CL4(a##9)

void f();

void a() {
  int b;
  if (b == 1) { f(); }
  CL4(1)
}

 Changing if (b == 1) to if (b) fixes the large compile time on gcc 4.0, but
keeps the large compile time problem with gcc 3.3 and 3.4.

-- 
           Summary: Lots of else ifs take forever to compile
           Product: gcc
           Version: 4.0.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: rtl-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: phython at gcc dot gnu dot org
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19097