diff options
-rw-r--r-- | gcc/ChangeLog | 5 | ||||
-rw-r--r-- | gcc/cse.c | 6 | ||||
-rw-r--r-- | gcc/testsuite/ChangeLog | 5 | ||||
-rw-r--r-- | gcc/testsuite/gcc.dg/pr53352.c | 41 |
4 files changed, 56 insertions, 1 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 320ae0d09cc..ea1941e17b9 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,8 @@ +2012-05-18 Meador Inge <meadori@codesourcery.com> + + PR rtl-optimization/53352 + * cse.c (equiv_constant): Ignore paradoxical subregs. + 2012-05-17 Steven Bosscher <steven@gcc.gnu.org> PR rtl-optimization/53125 diff --git a/gcc/cse.c b/gcc/cse.c index 0ad7b2e2a46..9f4e97932ed 100644 --- a/gcc/cse.c +++ b/gcc/cse.c @@ -3786,8 +3786,12 @@ equiv_constant (rtx x) } } - /* Otherwise see if we already have a constant for the inner REG. */ + /* Otherwise see if we already have a constant for the inner REG, + and if that is enough to calculate an equivalent constant for + the subreg. Note that the upper bits of paradoxical subregs + are undefined, so they cannot be said to equal anything. */ if (REG_P (SUBREG_REG (x)) + && GET_MODE_SIZE (mode) <= GET_MODE_SIZE (imode) && (new_rtx = equiv_constant (SUBREG_REG (x))) != 0) return simplify_subreg (mode, new_rtx, imode, SUBREG_BYTE (x)); diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 22f2982bbab..64a011c0e87 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2012-05-18 Meador Inge <meadori@codesourcery.com> + + PR rtl-optimization/53352 + * gcc.dg/pr53352.c: New test. + 2012-05-17 David S. Miller <davem@davemloft.net> * gfortran.dg/bessel_7.f90: Bump allowed precision to avoid diff --git a/gcc/testsuite/gcc.dg/pr53352.c b/gcc/testsuite/gcc.dg/pr53352.c new file mode 100644 index 00000000000..1d2edf8bb8c --- /dev/null +++ b/gcc/testsuite/gcc.dg/pr53352.c @@ -0,0 +1,41 @@ +/* { dg-do run } */ +/* { dg-options "-O1" } */ + +#include <stdlib.h> + +typedef union +{ + struct + { + unsigned char a; + unsigned char b; + unsigned char c; + unsigned char d; + } parts; + unsigned long whole; +} T; + +T *g_t; + +void bar (unsigned long x) +{ + if (x != 0) + abort (); +} + +int main () +{ + T one; + T two; + T tmp1, tmp2; + + one.whole = 0xFFE0E0E0UL; + two.whole = 0xFF000000UL; + tmp1.parts = two.parts; + tmp2.parts = one.parts; + tmp2.parts.c = tmp1.parts.c; + one.parts = tmp2.parts; + + g_t = &one; + bar (0); +} |