Hi, this patch back port trunk@198101 to fix PR rtl-optimization/56847. Passed bootstrap and regression test.
Ok for branch google/gcc-4_8? 2013-04-19 Vladimir Makarov <vmaka...@redhat.com> PR rtl-optimization/56847 * lra-constraints.c (process_alt_operands): Discourage alternative with non-matche doffsettable memory constraint fro memory with known offset. diff --git a/gcc/lra-constraints.c b/gcc/lra-constraints.c index e3b4add..9e4924c 100644 --- a/gcc/lra-constraints.c +++ b/gcc/lra-constraints.c @@ -1978,8 +1978,15 @@ process_alt_operands (int only_alternative) (op, this_alternative) == NO_REGS)))) reject += LRA_MAX_REJECT; - if (! ((const_to_mem && constmemok) - || (MEM_P (op) && offmemok))) + if (MEM_P (op) && offmemok) + { + /* If we know offset and this non-offsetable memory, + something wrong with this memory and it is better + to try other memory possibilities. */ + if (MEM_OFFSET_KNOWN_P (op)) + reject += LRA_MAX_REJECT; + } + else if (! (const_to_mem && constmemok)) { /* We prefer to reload pseudos over reloading other things, since such reloads may be able to be diff --git a/gcc/testsuite/gcc.dg/pr56847.c b/gcc/testsuite/gcc.dg/pr56847.c new file mode 100644 index 0000000..b94aae1 --- /dev/null +++ b/gcc/testsuite/gcc.dg/pr56847.c @@ -0,0 +1,12 @@ +/* PR rtl-optimization/56847 */ +/* { dg-do compile { target pie } } */ +/* { dg-options "-O2 -fpie" } */ + +struct S { long int a, b; } e; +__thread struct S s; + +void +foo (void) +{ + s = e; +} H.