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/ SGI Varsity Update 1998 August / SGI Varsity Update 1998 August.iso / docs6.4 / relnotes / c_fe / ch6.z / ch6
Text File  |  1998-07-29  |  14KB  |  594 lines
  1.  
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  4.                                                - 1 -
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  8.                     7.2.1 ANSI C Front-End Release Notes
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  69.                                                - 2 -
  70.  
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  72.  
  73.                     DDDDooooccccuuuummmmeeeennnntttt NNNNuuuummmmbbbbeeeerrrr 000000007777----1111666655559999----000011110000
  74.  
  75.  
  76.                     6.  _B_u_g__F_i_x_e_s
  77.  
  78.                     This chapter details bugs that have been fixed
  79.                     both for 7.2.1 and 7.2.
  80.  
  81.  
  82.                     6.1  _B_u_g__F_i_x_e_s__i_n__M_I_P_S_p_r_o__7_._2_._1
  83.  
  84.                     This section briefly describes the bugs that
  85.                     have been fixed in the compiler since release
  86.                     7.1.  Some of the headings are followed by a
  87.                     Silicon Graphics incident report number.
  88.  
  89.                        +o The IRIX sendmail program would produce
  90.                          incorrect results when compiled -O2. This
  91.                          has been fixed. (Bug 524374).
  92.  
  93.                        +o Incorrect expression evaluation of unsigned
  94.                          subtraction
  95.  
  96.                          The following program produces incorrect
  97.                          results for the first comparison when
  98.                          compiled -n32, and -64 with 7.2. -32
  99.                          compiles are OK.
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  135.                                                - 3 -
  136.  
  137.  
  138.  
  139.                          %cat JJ.c
  140.  
  141.                          typedef unsigned long fakelong;
  142.  
  143.                          #define SUBTRACT(p,q)   ((fakelong)(p) - (fakelong)(q))
  144.  
  145.                          main() {
  146.  
  147.                            char *a = "a";
  148.                            char *b = "b";
  149.                            char *c = "c";
  150.  
  151.                            /* the following comparison will compare a very large number and
  152.                               a small number.  */
  153.  
  154.                            if ((SUBTRACT(a,b)) <= (SUBTRACT(c,b))) {
  155.                              printf("You have incorrectly evaluated this expression.0);
  156.                            } else {
  157.                              printf("You have correctly evaluated this expression.0);
  158.                            }
  159.  
  160.                            printf("a is 0x%x  0, (fakelong)(a));
  161.                            printf("b is 0x%x  0, (fakelong)(b));
  162.                            printf("c is 0x%x  0, (fakelong)(c));
  163.  
  164.                            printf("diff a-b is 0x%x  0, (SUBTRACT(a,b)));
  165.                            printf("diff c-b is 0x%x  0, (SUBTRACT(c,b)));
  166.  
  167.                            if ( ( (unsigned) 0 - (unsigned) 8 ) <= ((unsigned) 16 - (unsigned) 8) ) {
  168.                              printf("You have incorrectly evaluated this expression.0);
  169.                            } else {
  170.                              printf("You have correctly evaluated this expression.0);
  171.                            }
  172.                          }
  173.  
  174.                          This has been fixed (Bug 536075).
  175.  
  176.  
  177.                        +o Limit on number of files which could be
  178.                          compiled from one cc command line when
  179.                          floating licenses were used
  180.  
  181.                          The C compiler would stop and issue the
  182.                          following warnings when trying to compile
  183.                          more files than the open file descriptor
  184.                          limit on a single command line under
  185.                          floating licensing.
  186.  
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  200.  
  201.                                                - 4 -
  202.  
  203.  
  204.  
  205.                          For Example:
  206.                             (Floating Licenses being used)
  207.  
  208.                          %limit descriptors
  209.                          descriptors     200
  210.  
  211.                          %cc  *.c          (more than 200 .c files in current directory)
  212.                          file196.c:
  213.                          cc: Error: can't create output file: /tmp/ctmpa001YG
  214.                             : Too many open files
  215.  
  216.  
  217.                          This has been fixed (Bug 556876).
  218.  
  219.  
  220.  
  221.  
  222.                     6.2  _B_u_g__F_i_x_e_s__i_n__M_I_P_S_p_r_o__7_._2
  223.  
  224.                     This section briefly describes the bugs that
  225.                     have been fixed in the compiler since release
  226.                     7.1.  Some of the headings are followed by a
  227.                     Silicon Graphics incident report number.
  228.  
  229.                        +o The following line of code was incorrectly
  230.                          being compiled under -n32 with MIPSpro 7.1
  231.  
  232.                          return ( ! !((!(error) || (*(error) == (1)))) )
  233.  
  234.                          This has been fixed (Bug 449456)
  235.  
  236.                        +o Under certain circumstances the C compiler
  237.                          would dump core with the following message:
  238.  
  239.                          Signal: Segmentation fault in Scope Setup phase.
  240.                          Error: Signal Segmentation fault in phase Scope Setup -- processing
  241.                          aborted
  242.                          cc ERROR:  /usr/lib32/cmplrs/fec died due to signal 4
  243.                          cc ERROR:  core dumped
  244.  
  245.                          This has been fixed (Bug 470114)
  246.  
  247.                        +o Incorrect code produced under optimization
  248.                          (-O2 or higher).
  249.                          The compiler incorrectly optimized the
  250.                          following code:  (A workaround was provided
  251.                          under the #ifdef OPT_BUG)
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  267.                                                - 5 -
  268.  
  269.  
  270.  
  271.  
  272.                              for (args = result; num_args1 != 0; num_args1--)
  273.                                  *args++ = *args1++;
  274.                          #ifdef OPT_BUG /* Workaround of compiler 7.1 bug */
  275.                              while (num_args2-- > 0)
  276.                          #else
  277.                              for (             ; num_args2 != 0; num_args2--)
  278.                          #endif
  279.                                  *args++ = *args2++;
  280.  
  281.                              return result
  282.  
  283.  
  284.                          This bug has been fixed. (Bug #428276)
  285.  
  286.                        +o Incorrect optimization under -O3.
  287.                          The following code would produce incorrect
  288.                          results when compiled under -O3:
  289.  
  290.  
  291.                          /* test1.c */
  292.                          #include <stdio.h>
  293.  
  294.                          main()
  295.  
  296.                          {
  297.                             char str[] = "1.2345";
  298.                             char *cp = str;
  299.                             char *cpe = NULL;
  300.  
  301.                             printf ("1. scp = %s, cp = %x0, cp, (unsigned int) cp);
  302.                             while (cp != cpe)
  303.                             {
  304.                                if (*cp++ == '.') break;
  305.                             }
  306.                             printf ("2. scp = %s, cp = %x0, cp, (unsigned int) cp);
  307.                          }
  308.  
  309.  
  310.  
  311.                          This has been fixed. (Bug #447872)
  312.  
  313.  
  314.                        +o Incorrect optimization under -O3.
  315.                          The following code would produce incorrect
  316.                          results when compiled under -O3:
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  333.                                                - 6 -
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  335.  
  336.  
  337.                          /* test1.c */
  338.                          #include <stdio.h>
  339.  
  340.                          main()
  341.  
  342.                          {
  343.                             char str[] = "1.2345";
  344.                             char *cp = str;
  345.                             char *cpe = NULL;
  346.  
  347.                             printf ("1. scp = %s, cp = %x0, cp, (unsigned int) cp);
  348.                             while (cp != cpe)
  349.                             {
  350.                                if (*cp++ == '.') break;
  351.                             }
  352.                             printf ("2. scp = %s, cp = %x0, cp, (unsigned int) cp);
  353.                          }
  354.  
  355.  
  356.  
  357.                          This has been fixed. (Bug #447872)
  358.  
  359.  
  360.                        +o Improper handling of __return_address
  361.                          The following code gets incorrectly
  362.                          compiled -n32 because the reference to
  363.                          __return_address causes the return address
  364.                          from buggy to be retrieved with incorrect
  365.                          sign extension.
  366.  
  367.                              void buggy() { bar(__return_address); }
  368.  
  369.                          This has been fixed. (Bug #460589)
  370.  
  371.                        +o INTERNAL ERROR when compiling C code with
  372.                          #pragma numthreads.
  373.                          The following example illustrates an
  374.                          INTERNAL ERROR in /usr/lib32/cmplrs/be:
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  399.                                                - 7 -
  400.  
  401.  
  402.  
  403.                          %cc -mp -O3 -xansi -64 -mips4 -TENV:X=1 -OPT:alias=restrict -c file.c
  404.  
  405.  
  406.                          ### Compiler Error in file irvcc2.c during MP Lowering phase:
  407.                          ### out of context pragma (NUMTHREADS) in MP processing
  408.                          cc INTERNAL ERROR:  /usr/lib32/cmplrs/be returned non-zero status 1
  409.  
  410.                          %cat file.c
  411.                          void
  412.                          fored (int *rmatbeg, int *rmatind, double *rmatval, int *rmatend,
  413.                          int rows, int cols, double *y, double *x, int maxthreads)
  414.                          {
  415.  
  416.                          int     i, j, j1, k, l;
  417.                          double  temp;
  418.  
  419.                             if ( mpc_in_parallel_region() )  maxthreads = 1;
  420.                          #pragma  parallel
  421.                          #pragma  numthreads (min=1;max=maxthreads)
  422.                          #pragma  shared (rmatbeg, rmatend, rmatind, rmatval, y, x, rows)
  423.                          #pragma  local (i, k, l, temp)
  424.                             {
  425.                          #pragma  pfor iterate(i=0;rows;1) schedtype(gss)
  426.                                for (i = 0; i < rows; i++) {
  427.                                   temp = 0.0;
  428.                                   l = rmatend[i];
  429.                          #pragma ivdep
  430.                                   for (k = rmatbeg[i]; k < l; k++) {
  431.                                      temp += rmatval[k]*x[rmatind[k]];
  432.                                   }
  433.                                   y[i] = temp;
  434.                                }  /* End for loop */
  435.                             }  /* End parallel section */
  436.  
  437.                          }
  438.  
  439.                          This has been fixed. (Bug #461670)
  440.  
  441.                        +o Incorrect promotion of formal arguments.
  442.                          The following code would produce incorrect
  443.                          results when compiled -64.
  444.  
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  464.  
  465.                                                - 8 -
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  468.  
  469.  
  470.                          #include <stdio.h>
  471.  
  472.                          int R_DIEDRE(xa,ya,za,xb,yb,zb,xc,yc,zc,xd,yd,zd)
  473.  
  474.                          float xa,ya,za;/* coord. du 1er atome */
  475.                          float xb,yb,zb;/* coord. du 2eme atome */
  476.                          float xc,yc,zc;/* coord. du 3eme atome */
  477.                          float xd,yd,zd;/* coord. du 4eme atome */
  478.                          {
  479.                           printf("%f %f %f %f %f %f %f %f %f %f %f
  480.                          %f0,xa,ya,za,xb,yb,zb,xc,yc,zc,xd,yd,zd);
  481.  
  482.                           return(0);
  483.                          }
  484.  
  485.  
  486.                          main()
  487.                          {
  488.                           float X[40],Y[40],Z[40],ang;
  489.  
  490.                           R_DIEDRE(123.4,123.4,123.4,
  491.                                    123.4,123.4,123.4,
  492.                                    123.4,123.4,123.4,
  493.                                    123.4,123.4,123.4);
  494.  
  495.                          }
  496.  
  497.  
  498.                          This has been fixed (Bug #465609).
  499.  
  500.                        +o Incorrect sign extension induced by
  501.                          optimizer
  502.                          Under certain circumstances the optimizer
  503.                          would produce code with values incorrectly
  504.                          sign extended.  This has been fixed (Bugs
  505.                          #467930 and #468670).
  506.  
  507.                        +o Assertion failure in compiler back-end.
  508.                          The following code would cause the
  509.                          compilation to fail for -n32 compiles:
  510.  
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  530.  
  531.                                                - 9 -
  532.  
  533.  
  534.  
  535.                          typedef struct bar {
  536.                              unsigned long  size;
  537.                              unsigned long  space;
  538.                          } bar;
  539.  
  540.                          typedef struct foo {
  541.                              bar      dict;
  542.                          } foo;
  543.  
  544.                          #define size(d)  ((d)->size-(d)->space)
  545.  
  546.                          void spam (foo *baz)
  547.                          {
  548.                              int flag = 1;
  549.  
  550.                              flag &= (size(&baz->dict) <= 4294967295U);
  551.                          }
  552.  
  553.                          This has been fixed (Bug #469411).
  554.  
  555.                        +o cc generates bad code when assigning to a
  556.                          variable in expression
  557.                          Under certain circumstances cc would
  558.                          generate bad code when assigning to a
  559.                          variable in an expression.  This has been
  560.                          fixed (Bug 462177).
  561.  
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