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| author | Meador Inge <meadori@codesourcery.com> | 2012-05-18 09:04:38 +0000 |
|---|---|---|
| committer | Richard Sandiford <rsandifo@gcc.gnu.org> | 2012-05-18 09:04:38 +0000 |
| commit | 7cb6668a1f251a35f26875398992eb4b1ae78f30 (patch) | |
| tree | 91ed913d04c3205957d44e36e2b7751a0fd287dd /gcc | |
| parent | 4a3afb1a3d9959742fc9279ffba9f9acd994d8f2 (diff) | |
| download | gcc-7cb6668a1f251a35f26875398992eb4b1ae78f30.zip gcc-7cb6668a1f251a35f26875398992eb4b1ae78f30.tar.gz gcc-7cb6668a1f251a35f26875398992eb4b1ae78f30.tar.bz2 | |
re PR rtl-optimization/53352 (Incorrect CSE optimization on RTL expressions with a paradoxical subreg)
gcc/
2012-05-15 Meador Inge <meadori@codesourcery.com>
PR rtl-optimization/53352
* cse.c (equiv_constant): Ignore paradoxical subregs.
gcc/testsuite/
2012-05-15 Meador Inge <meadori@codesourcery.com>
PR rtl-optimization/53352
* gcc.dg/pr53352.c: New test.
From-SVN: r187648
Diffstat (limited to 'gcc')
| -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 320ae0d..ea1941e 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 @@ -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 22f2982..64a011c 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 0000000..1d2edf8 --- /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); +} |