Test case added. Tested with make check-gcc RUNTESTFLAGS="--target_board=arm-sim/thumb/arch=armv7-a arm.exp=pr49799.c" make check-gcc RUNTESTFLAGS="--target_board=arm-sim/arch=armv7-a arm.exp=pr49799.c"
It fails without this patch and passes with this patch. OK for trunk and 4.6 now? thanks Carrot ChangeLog: 2011-07-28 Wei Guozhi <car...@google.com> PR rtl-optimization/49799 * combine.c (make_compound_operation): Check if the bit field is valid before change it to bit field extraction. ChangeLog: 2011-07-28 Wei Guozhi <car...@google.com> PR rtl-optimization/49799 * pr49799.c : New test case. Index: gcc/combine.c =================================================================== --- gcc/combine.c (revision 176733) +++ gcc/combine.c (working copy) @@ -7787,6 +7787,7 @@ make_compound_operation (rtx x, enum rtx && GET_CODE (lhs) == ASHIFT && CONST_INT_P (XEXP (lhs, 1)) && INTVAL (rhs) >= INTVAL (XEXP (lhs, 1)) + && INTVAL (XEXP (lhs, 1)) >= 0 && INTVAL (rhs) < mode_width) { new_rtx = make_compound_operation (XEXP (lhs, 0), next_code); Index: pr49799.c =================================================================== --- pr49799.c (revision 0) +++ pr49799.c (revision 0) @@ -0,0 +1,25 @@ +/* PR rtl-optimization/49799 */ +/* { dg-do assemble } */ +/* { dg-options "-O2 -w -march=armv7-a" } */ + +static __inline int bar(int a) +{ + int tmp; + + if (a <= 0) a ^= 0xFFFFFFFF; + + return tmp - 1; +} + +void foo(short *K) +{ + short tmp; + short *pptr, P[14]; + + pptr = P; + tmp = bar(*K); + *pptr = (*K << tmp) >> 16; + + if (*P < tmp) + *K++ = 0; +} On Thu, Jul 28, 2011 at 4:04 PM, Jakub Jelinek <ja...@redhat.com> wrote: > On Thu, Jul 28, 2011 at 03:38:07PM +0800, Carrot Wei wrote: >> OK for trunk and 4.6? >> >> ChangeLog: >> 2011-07-28 Wei Guozhi <car...@google.com> >> >> PR rtl-optimization/49799 >> * combine.c (make_compound_operation): Check if the bit field is >> valid >> before change it to bit field extraction. > > Looks good to me, handling SHIFT_COUNT_TRUNCATED here isn't IMHO necessary > and the checking whether shift count is in the right range matches other rtx > simplifications (e.g. in simplify-rtx.c). > Though, you should add a testcase, probably > /* PR rtl-optimization/49799 */ > /* { dg-do assemble } */ > /* { dg-options "-O2 -w" } */ > > plus not sure if for arm you don't want to force this -march=armv7-a > into dg-options too or just leave it as is. > > Jakub >