| Message ID | 20161129140815.GA441@x4 |
|---|---|
| State | New |
| Headers | show |
On Tue, Nov 29, 2016 at 03:08:15PM +0100, Markus Trippelsdorf wrote: > Building gcc with -fsanitize=undefined shows: > rtlanal.c:5210:38: runtime error: shift exponent 4294967295 is too > large for 64-bit type 'long unsigned int' > > 5210 return nonzero & (HOST_WIDE_INT_1U << (bitwidth - 1)) > 5211 ? 1 : bitwidth - floor_log2 (nonzero) - 1; > > Here (bitwidth - 1) wraps around because bitwidth is zero and unsigned. Which modes have precision of 0? I'd expect just VOIDmode and BLKmode, any others? And for those I'd say it is a bug to call num_sign_bit_copies*. > Tested on ppc64le. > OK for trunk? > > Thanks. > > * rtlanal.c (num_sign_bit_copies1): Check for zero bitwidth. > > diff --git a/gcc/rtlanal.c b/gcc/rtlanal.c > index 4e4eb2ef3458..918088a0db8e 100644 > --- a/gcc/rtlanal.c > +++ b/gcc/rtlanal.c > @@ -5203,7 +5203,7 @@ num_sign_bit_copies1 (const_rtx x, machine_mode mode, const_rtx known_x, > safely compute the mask for this mode, always return BITWIDTH. */ > > bitwidth = GET_MODE_PRECISION (mode); > - if (bitwidth > HOST_BITS_PER_WIDE_INT) > + if (bitwidth == 0 || bitwidth > HOST_BITS_PER_WIDE_INT) > return 1; > > nonzero = nonzero_bits (x, mode); > > -- > Markus Jakub
On 2016.11.29 at 15:14 +0100, Jakub Jelinek wrote: > On Tue, Nov 29, 2016 at 03:08:15PM +0100, Markus Trippelsdorf wrote: > > Building gcc with -fsanitize=undefined shows: > > rtlanal.c:5210:38: runtime error: shift exponent 4294967295 is too > > large for 64-bit type 'long unsigned int' > > > > 5210 return nonzero & (HOST_WIDE_INT_1U << (bitwidth - 1)) > > 5211 ? 1 : bitwidth - floor_log2 (nonzero) - 1; > > > > Here (bitwidth - 1) wraps around because bitwidth is zero and unsigned. > > Which modes have precision of 0? I'd expect just VOIDmode and BLKmode, any > others? And for those I'd say it is a bug to call num_sign_bit_copies*. Yes, only VOIDmode and BLKmode: 233 const unsigned short mode_precision[NUM_MACHINE_MODES] = 234 { 235 0, /* VOID */ 236 0, /* BLK */ -- Markus
On 2016.11.29 at 15:21 +0100, Markus Trippelsdorf wrote: > On 2016.11.29 at 15:14 +0100, Jakub Jelinek wrote: > > On Tue, Nov 29, 2016 at 03:08:15PM +0100, Markus Trippelsdorf wrote: > > > Building gcc with -fsanitize=undefined shows: > > > rtlanal.c:5210:38: runtime error: shift exponent 4294967295 is too > > > large for 64-bit type 'long unsigned int' > > > > > > 5210 return nonzero & (HOST_WIDE_INT_1U << (bitwidth - 1)) > > > 5211 ? 1 : bitwidth - floor_log2 (nonzero) - 1; > > > > > > Here (bitwidth - 1) wraps around because bitwidth is zero and unsigned. > > > > Which modes have precision of 0? I'd expect just VOIDmode and BLKmode, any > > others? And for those I'd say it is a bug to call num_sign_bit_copies*. > > Yes, only VOIDmode and BLKmode: > > 233 const unsigned short mode_precision[NUM_MACHINE_MODES] = > 234 { > 235 0, /* VOID */ > 236 0, /* BLK */ markus@x4 libsupc++ % cat cp-demangle.i d_demangle_callback_mangled() { if (strncmp(d_demangle_callback_mangled, "", 1)) d_type(); } markus@x4 libsupc++ % UBSAN_OPTIONS=print_stacktrace=1:halt_on_error=1 /var/tmp/gcc_build_dir_/./gcc/cc1 -w -fpreprocessed cp-demangle.i -quiet -dumpbase cp-demangle.i -mtune=generic -march=x86-64 -auxbase cp-demangle -O2 -version -o /dev/null GNU C11 (GCC) version 7.0.0 20161129 (experimental) (x86_64-pc-linux-gnu) compiled by GNU C version 7.0.0 20161129 (experimental), GMP version 6.1.1, MPFR version 3.1.5, MPC version 1.0.3, isl version none GGC heuristics: --param ggc-min-expand=30 --param ggc-min-heapsize=4096 GNU C11 (GCC) version 7.0.0 20161129 (experimental) (x86_64-pc-linux-gnu) compiled by GNU C version 7.0.0 20161129 (experimental), GMP version 6.1.1, MPFR version 3.1.5, MPC version 1.0.3, isl version none GGC heuristics: --param ggc-min-expand=30 --param ggc-min-heapsize=4096 Compiler executable checksum: 7cca725773f8a0693a2905f8af7b733c ../../gcc/gcc/rtlanal.c:5210:38: runtime error: shift exponent 4294967295 is too large for 64-bit type 'long unsigned int' #0 0x1b40fe1 in num_sign_bit_copies1 ../../gcc/gcc/rtlanal.c:5210 #1 0x35ef5f1 in if_then_else_cond ../../gcc/gcc/combine.c:9180 #2 0x35ef199 in if_then_else_cond ../../gcc/gcc/combine.c:9034 #3 0x35ef199 in if_then_else_cond ../../gcc/gcc/combine.c:9034 #4 0x3625f98 in combine_simplify_rtx ../../gcc/gcc/combine.c:5604 #5 0x3632525 in subst ../../gcc/gcc/combine.c:5487 #6 0x36327d6 in subst ../../gcc/gcc/combine.c:5425 #7 0x3632bd7 in subst ../../gcc/gcc/combine.c:5354 #8 0x3641a74 in try_combine ../../gcc/gcc/combine.c:3347 #9 0x365727b in combine_instructions ../../gcc/gcc/combine.c:1421 #10 0x365727b in rest_of_handle_combine ../../gcc/gcc/combine.c:14581 #11 0x365727b in execute ../../gcc/gcc/combine.c:14626 #12 0x195ad18 in execute_one_pass(opt_pass*) ../../gcc/gcc/passes.c:2370 #13 0x195cbab in execute_pass_list_1 ../../gcc/gcc/passes.c:2459 #14 0x195cbd4 in execute_pass_list_1 ../../gcc/gcc/passes.c:2460 #15 0x195cc64 in execute_pass_list(function*, opt_pass*) ../../gcc/gcc/passes.c:2470 #16 0xc75deb in cgraph_node::expand() ../../gcc/gcc/cgraphunit.c:2001 #17 0xc7b2fa in expand_all_functions ../../gcc/gcc/cgraphunit.c:2137 #18 0xc7b2fa in symbol_table::compile() ../../gcc/gcc/cgraphunit.c:2494 #19 0xc854b7 in symbol_table::compile() ../../gcc/gcc/cgraphunit.c:2587 #20 0xc854b7 in symbol_table::finalize_compilation_unit() ../../gcc/gcc/cgraphunit.c:2584 #21 0x1d3ea10 in compile_file ../../gcc/gcc/toplev.c:488 #22 0x629a14 in do_compile ../../gcc/gcc/toplev.c:1983 #23 0x629a14 in toplev::main(int, char**) ../../gcc/gcc/toplev.c:2117 #24 0x62c046 in main ../../gcc/gcc/main.c:39 #25 0x7f4b6600f310 in __libc_start_main ../csu/libc-start.c:286 #26 0x62c469 in _start (/var/tmp/gcc_build_dir_/gcc/cc1+0x62c469)
On 2016.11.29 at 16:01 +0100, Markus Trippelsdorf wrote: > On 2016.11.29 at 15:21 +0100, Markus Trippelsdorf wrote: > > On 2016.11.29 at 15:14 +0100, Jakub Jelinek wrote: > > > On Tue, Nov 29, 2016 at 03:08:15PM +0100, Markus Trippelsdorf wrote: > > > > Building gcc with -fsanitize=undefined shows: > > > > rtlanal.c:5210:38: runtime error: shift exponent 4294967295 is too > > > > large for 64-bit type 'long unsigned int' > > > > > > > > 5210 return nonzero & (HOST_WIDE_INT_1U << (bitwidth - 1)) > > > > 5211 ? 1 : bitwidth - floor_log2 (nonzero) - 1; > > > > > > > > Here (bitwidth - 1) wraps around because bitwidth is zero and unsigned. > > > > > > Which modes have precision of 0? I'd expect just VOIDmode and BLKmode, any > > > others? And for those I'd say it is a bug to call num_sign_bit_copies*. > > > > Yes, only VOIDmode and BLKmode: > > > > 233 const unsigned short mode_precision[NUM_MACHINE_MODES] = > > 234 { > > 235 0, /* VOID */ > > 236 0, /* BLK */ > > markus@x4 libsupc++ % cat cp-demangle.i > d_demangle_callback_mangled() { > if (strncmp(d_demangle_callback_mangled, "", 1)) > d_type(); > } > > markus@x4 libsupc++ % UBSAN_OPTIONS=print_stacktrace=1:halt_on_error=1 /var/tmp/gcc_build_dir_/./gcc/cc1 -w -fpreprocessed cp-demangle.i -quiet -dumpbase cp-demangle.i -mtune=generic -march=x86-64 -auxbase cp-demangle -O2 -version -o /dev/null > GNU C11 (GCC) version 7.0.0 20161129 (experimental) (x86_64-pc-linux-gnu) > compiled by GNU C version 7.0.0 20161129 (experimental), GMP version 6.1.1, MPFR version 3.1.5, MPC version 1.0.3, isl version none > GGC heuristics: --param ggc-min-expand=30 --param ggc-min-heapsize=4096 > GNU C11 (GCC) version 7.0.0 20161129 (experimental) (x86_64-pc-linux-gnu) > compiled by GNU C version 7.0.0 20161129 (experimental), GMP version 6.1.1, MPFR version 3.1.5, MPC version 1.0.3, isl version none > GGC heuristics: --param ggc-min-expand=30 --param ggc-min-heapsize=4096 > Compiler executable checksum: 7cca725773f8a0693a2905f8af7b733c > ../../gcc/gcc/rtlanal.c:5210:38: runtime error: shift exponent 4294967295 is too large for 64-bit type 'long unsigned int' > #0 0x1b40fe1 in num_sign_bit_copies1 ../../gcc/gcc/rtlanal.c:5210 > #1 0x35ef5f1 in if_then_else_cond ../../gcc/gcc/combine.c:9180 > #2 0x35ef199 in if_then_else_cond ../../gcc/gcc/combine.c:9034 > #3 0x35ef199 in if_then_else_cond ../../gcc/gcc/combine.c:9034 > #4 0x3625f98 in combine_simplify_rtx ../../gcc/gcc/combine.c:5604 > #5 0x3632525 in subst ../../gcc/gcc/combine.c:5487 > #6 0x36327d6 in subst ../../gcc/gcc/combine.c:5425 > #7 0x3632bd7 in subst ../../gcc/gcc/combine.c:5354 > #8 0x3641a74 in try_combine ../../gcc/gcc/combine.c:3347 > #9 0x365727b in combine_instructions ../../gcc/gcc/combine.c:1421 > #10 0x365727b in rest_of_handle_combine ../../gcc/gcc/combine.c:14581 > #11 0x365727b in execute ../../gcc/gcc/combine.c:14626 > #12 0x195ad18 in execute_one_pass(opt_pass*) ../../gcc/gcc/passes.c:2370 > #13 0x195cbab in execute_pass_list_1 ../../gcc/gcc/passes.c:2459 > #14 0x195cbd4 in execute_pass_list_1 ../../gcc/gcc/passes.c:2460 > #15 0x195cc64 in execute_pass_list(function*, opt_pass*) ../../gcc/gcc/passes.c:2470 > #16 0xc75deb in cgraph_node::expand() ../../gcc/gcc/cgraphunit.c:2001 > #17 0xc7b2fa in expand_all_functions ../../gcc/gcc/cgraphunit.c:2137 > #18 0xc7b2fa in symbol_table::compile() ../../gcc/gcc/cgraphunit.c:2494 > #19 0xc854b7 in symbol_table::compile() ../../gcc/gcc/cgraphunit.c:2587 > #20 0xc854b7 in symbol_table::finalize_compilation_unit() ../../gcc/gcc/cgraphunit.c:2584 > #21 0x1d3ea10 in compile_file ../../gcc/gcc/toplev.c:488 > #22 0x629a14 in do_compile ../../gcc/gcc/toplev.c:1983 > #23 0x629a14 in toplev::main(int, char**) ../../gcc/gcc/toplev.c:2117 > #24 0x62c046 in main ../../gcc/gcc/main.c:39 > #25 0x7f4b6600f310 in __libc_start_main ../csu/libc-start.c:286 > #26 0x62c469 in _start (/var/tmp/gcc_build_dir_/gcc/cc1+0x62c469) (gdb) p mode $1 = BLKmode #6 0x00000000035ef5f2 in if_then_else_cond (x=0x7ffff60d3888, ptrue=ptrue@entry=0x7fffffffd940, pfalse=pfalse@entry=0x7fffffffd950) at ../../gcc/gcc/combine.c:9180 9180 && num_sign_bit_copies (x, mode) == GET_MODE_PRECISION (mode))) (gdb) l 9175 9176 /* If X is known to be either 0 or -1, those are the true and 9177 false values when testing X. */ 9178 else if (x == constm1_rtx || x == const0_rtx 9179 || (mode != VOIDmode 9180 && num_sign_bit_copies (x, mode) == GET_MODE_PRECISION (mode))) 9181 { 9182 *ptrue = constm1_rtx, *pfalse = const0_rtx; 9183 return x; 9184 }
diff --git a/gcc/rtlanal.c b/gcc/rtlanal.c index 4e4eb2ef3458..918088a0db8e 100644 --- a/gcc/rtlanal.c +++ b/gcc/rtlanal.c @@ -5203,7 +5203,7 @@ num_sign_bit_copies1 (const_rtx x, machine_mode mode, const_rtx known_x, safely compute the mask for this mode, always return BITWIDTH. */ bitwidth = GET_MODE_PRECISION (mode); - if (bitwidth > HOST_BITS_PER_WIDE_INT) + if (bitwidth == 0 || bitwidth > HOST_BITS_PER_WIDE_INT) return 1; nonzero = nonzero_bits (x, mode);