re PR tree-optimization/53265 (Warn when undefined behavior implies smaller iteration count)
PR tree-optimization/53265 * common.opt (Waggressive-loop-optimizations): New option. * tree-ssa-loop-niter.c: Include tree-pass.h. (do_warn_aggressive_loop_optimizations): New function. (record_estimate): Call it. Don't add !is_exit bounds to loop->bounds if number_of_latch_executions returned constant. (estimate_numbers_of_iterations_loop): Call number_of_latch_executions early. If number_of_latch_executions returned constant, set nb_iterations_upper_bound back to it. * cfgloop.h (struct loop): Add warned_aggressive_loop_optimizations field. * Makefile.in (tree-ssa-loop-niter.o): Depend on $(TREE_PASS_H). * doc/invoke.texi (-Wno-aggressive-loop-optimizations): Document. * gcc.dg/pr53265.c: New test. * gcc.dg/torture/pr49518.c: Add -Wno-aggressive-loop-optimizations to dg-options. * g++.dg/opt/longbranch2.C (EBCOTLut): Double sizes of a2 and a3 arrays. * gcc.dg/tree-ssa/cunroll-10.c (main): Rename to foo. Add argument n, use it as high bound instead of 4. * unwind-dw2.c (execute_cfa_program): Avoid -Waggressive-array-optimizations warnings for DW_CFA_GNU_window_save on targets with DWARF_FRAME_REGISTERS < 32. * testsuite/libmudflap.c/fail37-frag.c: Add optimization barrier. From-SVN: r196650
This commit is contained in:
Jakub Jelinek
Jakub Jelinek
parent
df2dfaea4e
commit
fbd28bc3b2
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@ -1,5 +1,19 @@
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2013-03-14 Jakub Jelinek <jakub@redhat.com>
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PR tree-optimization/53265
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* common.opt (Waggressive-loop-optimizations): New option.
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* tree-ssa-loop-niter.c: Include tree-pass.h.
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(do_warn_aggressive_loop_optimizations): New function.
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(record_estimate): Call it. Don't add !is_exit bounds to loop->bounds
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if number_of_latch_executions returned constant.
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(estimate_numbers_of_iterations_loop): Call number_of_latch_executions
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early. If number_of_latch_executions returned constant, set
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nb_iterations_upper_bound back to it.
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* cfgloop.h (struct loop): Add warned_aggressive_loop_optimizations
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field.
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* Makefile.in (tree-ssa-loop-niter.o): Depend on $(TREE_PASS_H).
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* doc/invoke.texi (-Wno-aggressive-loop-optimizations): Document.
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* config/aarch64/t-aarch64-linux (MULTARCH_DIRNAME): Remove.
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(MULTILIB_OSDIRNAMES): Set.
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* genmultilib: If defaultosdirname doesn't start with :: , set
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@ -2446,7 +2446,7 @@ tree-ssa-loop-niter.o : tree-ssa-loop-niter.c $(TREE_FLOW_H) $(CONFIG_H) \
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$(SYSTEM_H) $(TREE_H) $(TM_P_H) $(CFGLOOP_H) $(PARAMS_H) \
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$(TREE_INLINE_H) $(DIAGNOSTIC_H) $(TM_H) coretypes.h dumpfile.h \
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$(DIAGNOSTIC_CORE_H) $(FLAGS_H) $(TREE_DATA_REF_H) \
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$(BASIC_BLOCK_H) $(GGC_H) intl.h $(GIMPLE_PRETTY_PRINT_H)
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$(BASIC_BLOCK_H) $(GGC_H) intl.h $(GIMPLE_PRETTY_PRINT_H) $(TREE_PASS_H)
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tree-ssa-loop-ivcanon.o : tree-ssa-loop-ivcanon.c $(TREE_FLOW_H) $(CONFIG_H) \
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$(SYSTEM_H) $(TREE_H) $(TM_P_H) $(CFGLOOP_H) $(PARAMS_H) \
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$(TREE_INLINE_H) $(DIAGNOSTIC_H) $(TM_H) coretypes.h \
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@ -159,6 +159,10 @@ struct GTY ((chain_next ("%h.next"))) loop {
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/* True if the loop can be parallel. */
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bool can_be_parallel;
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/* True if -Waggressive-loop-optimizations warned about this loop
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already. */
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bool warned_aggressive_loop_optimizations;
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/* An integer estimation of the number of iterations. Estimate_state
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describes what is the state of the estimation. */
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enum loop_estimation estimate_state;
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@ -505,6 +505,10 @@ Waggregate-return
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Common Var(warn_aggregate_return) Warning
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Warn about returning structures, unions or arrays
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Waggressive-loop-optimizations
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Common Var(warn_aggressive_loop_optimizations) Init(1) Warning
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Warn if a loop with constant number of iterations triggers undefined behavior
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Warray-bounds
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Common Var(warn_array_bounds) Warning
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Warn if an array is accessed out of bounds
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@ -232,7 +232,8 @@ Objective-C and Objective-C++ Dialects}.
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@xref{Warning Options,,Options to Request or Suppress Warnings}.
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@gccoptlist{-fsyntax-only -fmax-errors=@var{n} -Wpedantic @gol
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-pedantic-errors @gol
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-w -Wextra -Wall -Waddress -Waggregate-return -Warray-bounds @gol
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-w -Wextra -Wall -Waddress -Waggregate-return @gol
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-Waggressive-loop-optimizations -Warray-bounds @gol
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-Wno-attributes -Wno-builtin-macro-redefined @gol
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-Wc++-compat -Wc++11-compat -Wcast-align -Wcast-qual @gol
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-Wchar-subscripts -Wclobbered -Wcomment @gol
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@ -4423,6 +4424,12 @@ Warn if any functions that return structures or unions are defined or
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called. (In languages where you can return an array, this also elicits
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a warning.)
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@item -Wno-aggressive-loop-optimizations
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@opindex Wno-aggressive-loop-optimizations
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@opindex Waggressive-loop-optimizations
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Warn if in a loop with constant number of iterations the compiler detects
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undefined behavior in some statement during one or more of the iterations.
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@item -Wno-attributes
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@opindex Wno-attributes
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@opindex Wattributes
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@ -1,3 +1,14 @@
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2013-03-14 Jakub Jelinek <jakub@redhat.com>
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PR tree-optimization/53265
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* gcc.dg/pr53265.c: New test.
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* gcc.dg/torture/pr49518.c: Add -Wno-aggressive-loop-optimizations
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to dg-options.
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* g++.dg/opt/longbranch2.C (EBCOTLut): Double sizes of a2 and a3
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arrays.
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* gcc.dg/tree-ssa/cunroll-10.c (main): Rename to foo. Add argument
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n, use it as high bound instead of 4.
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2013-03-13 Oleg Endo <olegendo@gcc.gnu.org>
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PR target/49880
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@ -15,8 +15,8 @@ public:
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class EBCOTLut : public JKeeper {
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unsigned char a1[1<<8];
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unsigned char a2[1<<8];
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unsigned char a3[1<<8];
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unsigned char a2[1<<9];
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unsigned char a3[1<<9];
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long a4[1<<9];
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public:
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EBCOTLut(void);
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@ -0,0 +1,156 @@
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/* PR tree-optimization/53265 */
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/* { dg-do compile } */
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/* { dg-options "-O2 -Wall" } */
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void bar (void *);
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int baz (int);
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void
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fn1 (void)
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{
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unsigned int a[128];
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int i;
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for (i = 0; i < 128; ++i) /* { dg-message "note: containing loop" } */
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a[i] = i * 0x02000001; /* { dg-warning "invokes undefined behavior" } */
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bar (a);
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}
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void
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fn2 (void)
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{
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unsigned long long a[128];
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int i;
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for (i = 0; i < 128; i++) /* { dg-message "note: containing loop" } */
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a[i] = (i + 1LL) * 0x0123456789ABCDEFLL; /* { dg-warning "invokes undefined behavior" } */
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bar (a);
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}
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void
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fn3 (void)
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{
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unsigned char a[16], b[16], c[16];
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int i;
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bar (b);
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for (i = 0; i < (int) (sizeof (a) / sizeof (a[0])); i++) /* { dg-message "note: containing loop" } */
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{
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c[i + 8] = b[i]; /* { dg-warning "invokes undefined behavior" } */
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a[i + 8] = b[i + 8];
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}
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bar (a);
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bar (c);
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}
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void
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fn4 (void)
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{
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unsigned int *a[32], *o, i;
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bar (a);
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for (i = 0; i <= sizeof (a) / sizeof (a[0]); i++) /* { dg-message "note: containing loop" "" { xfail *-*-* } } */
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{
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o = a[i]; /* { dg-warning "invokes undefined behavior" "" { xfail *-*-* } } */
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bar (o);
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}
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}
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void
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fn5 (void)
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{
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unsigned short a[23940];
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unsigned int b[1140];
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int j;
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bar (b);
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for (j = 0; j < 1140; j++) /* { dg-message "note: containing loop" } */
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a[23940 + j - 950] = b[j]; /* { dg-warning "invokes undefined behavior" } */
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bar (a);
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}
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void
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fn6 (void)
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{
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double a[4][3], b[12];
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int i;
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bar (b);
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for (i = 0; i < 12; i++) /* { dg-message "note: containing loop" } */
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a[0][i] = b[i] / 10000.0; /* { dg-warning "invokes undefined behavior" } */
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bar (a);
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}
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void
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fn7 (void)
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{
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int a[16], b, c;
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bar (a);
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for (b = a[c = 0]; c < 16; b = a[++c]) /* { dg-warning "invokes undefined behavior" "" { xfail *-*-* } } */
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baz (b);
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}
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/* { dg-message "note: containing loop" "" { xfail *-*-* } 88 } */
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const void *va, *vb, *vc, *vd, *ve;
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const void *vf[4];
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void
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fn8 (void)
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{
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unsigned long i;
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vf[0] = va; vf[1] = vb; vf[2] = vc; vf[3] = vd;
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for (i = 0; i < (sizeof (vf) / sizeof (vf[0])); i++)
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if (!vf[i])
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vf[i] = ve;
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}
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int wa, wb[53][5], wc[53][5];
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void
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fn9 (void)
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{
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int i, j, k;
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for (i = 0; i < 53; i++)
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for (j = 16 / (((wa & 1) != 0) ? 8 : 4); j > 0; j--)
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{
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int d = 1;
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if (wb[i][j] == 0 || wc[i][1] != 0)
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continue;
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for (k = 0; k < j; k++)
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if (wc[i + k][1])
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{
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d = 0;
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break;
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}
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if (!d)
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continue;
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wc[i][j] = baz (0);
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}
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}
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int xa[18];
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void
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fn10 (void)
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{
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int i;
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for (i = 16; i < 32; i++) /* { dg-message "note: containing loop" } */
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xa[i] = 26; /* { dg-warning "invokes undefined behavior" } */
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}
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__attribute__((noinline)) static void
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fn11 (int x)
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{
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int i = 1;
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if (x > 1)
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do
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baz (i);
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while (++i != x); /* { dg-bogus "invokes undefined behavior" } */
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}
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void
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fn12 (void)
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{
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fn11 (1);
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fn11 (1);
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fn11 (1);
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}
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@ -1,4 +1,5 @@
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/* { dg-do compile } */
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/* { dg-options "-Wno-aggressive-loop-optimizations" } */
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int a, b;
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struct S { unsigned int s, t, u; } c, d = { 0, 1, 0 };
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@ -2,10 +2,11 @@
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/* { dg-options "-O3 -Warray-bounds -fdump-tree-cunroll-details" } */
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int a[3];
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int b[4];
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main()
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int
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foo (int n)
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{
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int i;
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for (i=0;i<4;i++)
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for (i=0;i<n;i++)
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if (b[i]==2)
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a[i]++;
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}
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@ -37,6 +37,7 @@ along with GCC; see the file COPYING3. If not see
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#include "flags.h"
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#include "diagnostic-core.h"
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#include "tree-inline.h"
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#include "tree-pass.h"
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#define SWAP(X, Y) do { affine_iv *tmp = (X); (X) = (Y); (Y) = tmp; } while (0)
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@ -2525,6 +2526,40 @@ record_niter_bound (struct loop *loop, double_int i_bound, bool realistic,
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loop->nb_iterations_estimate = loop->nb_iterations_upper_bound;
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}
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/* Emit a -Waggressive-loop-optimizations warning if needed. */
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static void
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do_warn_aggressive_loop_optimizations (struct loop *loop,
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double_int i_bound, gimple stmt)
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{
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/* Don't warn if the loop doesn't have known constant bound. */
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if (!loop->nb_iterations
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|| TREE_CODE (loop->nb_iterations) != INTEGER_CST
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|| !warn_aggressive_loop_optimizations
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/* To avoid warning multiple times for the same loop,
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only start warning when we preserve loops. */
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|| (cfun->curr_properties & PROP_loops) == 0
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/* Only warn once per loop. */
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|| loop->warned_aggressive_loop_optimizations
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/* Only warn if undefined behavior gives us lower estimate than the
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known constant bound. */
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|| i_bound.ucmp (tree_to_double_int (loop->nb_iterations)) >= 0
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/* And undefined behavior happens unconditionally. */
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|| !dominated_by_p (CDI_DOMINATORS, loop->latch, gimple_bb (stmt)))
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return;
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edge e = single_exit (loop);
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if (e == NULL)
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return;
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gimple estmt = last_stmt (e->src);
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warning_at (gimple_location (stmt), OPT_Waggressive_loop_optimizations,
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"iteration %E invokes undefined behavior",
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double_int_to_tree (TREE_TYPE (loop->nb_iterations), i_bound));
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inform (gimple_location (estmt), "containing loop");
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loop->warned_aggressive_loop_optimizations = true;
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}
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/* Records that AT_STMT is executed at most BOUND + 1 times in LOOP. IS_EXIT
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is true if the loop is exited immediately after STMT, and this exit
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is taken at last when the STMT is executed BOUND + 1 times.
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@ -2560,8 +2595,12 @@ record_estimate (struct loop *loop, tree bound, double_int i_bound,
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return;
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/* If we have a guaranteed upper bound, record it in the appropriate
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list. */
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if (upper)
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list, unless this is an !is_exit bound (i.e. undefined behavior in
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at_stmt) in a loop with known constant number of iterations. */
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if (upper
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&& (is_exit
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|| loop->nb_iterations == NULL_TREE
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|| TREE_CODE (loop->nb_iterations) != INTEGER_CST))
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{
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struct nb_iter_bound *elt = ggc_alloc_nb_iter_bound ();
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@ -2591,6 +2630,8 @@ record_estimate (struct loop *loop, tree bound, double_int i_bound,
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if (i_bound.ult (delta))
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return;
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if (upper && !is_exit)
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do_warn_aggressive_loop_optimizations (loop, i_bound, at_stmt);
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record_niter_bound (loop, i_bound, realistic, upper);
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}
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@ -3311,6 +3352,11 @@ estimate_numbers_of_iterations_loop (struct loop *loop)
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/* Force estimate compuation but leave any existing upper bound in place. */
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loop->any_estimate = false;
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/* Ensure that loop->nb_iterations is computed if possible. If it turns out
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to be constant, we avoid undefined behavior implied bounds and instead
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diagnose those loops with -Waggressive-loop-optimizations. */
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number_of_latch_executions (loop);
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exits = get_loop_exit_edges (loop);
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likely_exit = single_likely_exit (loop);
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FOR_EACH_VEC_ELT (exits, i, ex)
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@ -3345,6 +3391,17 @@ estimate_numbers_of_iterations_loop (struct loop *loop)
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bound = gcov_type_to_double_int (nit);
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record_niter_bound (loop, bound, true, false);
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}
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/* If we know the exact number of iterations of this loop, try to
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not break code with undefined behavior by not recording smaller
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maximum number of iterations. */
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if (loop->nb_iterations
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&& TREE_CODE (loop->nb_iterations) == INTEGER_CST)
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{
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loop->any_upper_bound = true;
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loop->nb_iterations_upper_bound
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= tree_to_double_int (loop->nb_iterations);
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}
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}
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/* Sets NIT to the estimated number of executions of the latch of the
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|
|
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|
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@ -1,3 +1,10 @@
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2013-03-14 Jakub Jelinek <jakub@redhat.com>
|
||||
|
||||
PR tree-optimization/53265
|
||||
* unwind-dw2.c (execute_cfa_program): Avoid
|
||||
-Waggressive-array-optimizations warnings for DW_CFA_GNU_window_save
|
||||
on targets with DWARF_FRAME_REGISTERS < 32.
|
||||
|
||||
2013-03-13 Oleg Endo <olegendo@gcc.gnu.org>
|
||||
|
||||
PR target/49880
|
||||
|
|
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|||
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@ -1128,11 +1128,12 @@ execute_cfa_program (const unsigned char *insn_ptr,
|
|||
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||||
case DW_CFA_GNU_window_save:
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||||
/* ??? Hardcoded for SPARC register window configuration. */
|
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for (reg = 16; reg < 32; ++reg)
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{
|
||||
fs->regs.reg[reg].how = REG_SAVED_OFFSET;
|
||||
fs->regs.reg[reg].loc.offset = (reg - 16) * sizeof (void *);
|
||||
}
|
||||
if (DWARF_FRAME_REGISTERS >= 32)
|
||||
for (reg = 16; reg < 32; ++reg)
|
||||
{
|
||||
fs->regs.reg[reg].how = REG_SAVED_OFFSET;
|
||||
fs->regs.reg[reg].loc.offset = (reg - 16) * sizeof (void *);
|
||||
}
|
||||
break;
|
||||
|
||||
case DW_CFA_GNU_args_size:
|
||||
|
|
|
|||
|
|
@ -1,3 +1,8 @@
|
|||
2013-03-14 Jakub Jelinek <jakub@redhat.com>
|
||||
|
||||
PR tree-optimization/53265
|
||||
* testsuite/libmudflap.c/fail37-frag.c: Add optimization barrier.
|
||||
|
||||
2013-02-03 Richard Sandiford <rdsandiford@googlemail.com>
|
||||
|
||||
Update copyright years.
|
||||
|
|
|
|||
|
|
@ -13,7 +13,11 @@ main ()
|
|||
{
|
||||
int i;
|
||||
for (i = 0; i < 5; i++)
|
||||
x.s[i].f = 0;
|
||||
{
|
||||
/* Optimization barrier. Prevent gcc from seeing the undefined behavior. */
|
||||
__asm ("" : "+r" (i));
|
||||
x.s[i].f = 0;
|
||||
}
|
||||
exit (0);
|
||||
}
|
||||
/* { dg-output "mudflap violation 1.*" } */
|
||||
|
|
|
|||
Loading…
Reference in New Issue