diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 638c0da2d295..ddebba79f84e 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,11 @@ +2014-04-23 Jeff Law + + PR tree-optimization/60902 + * tree-ssa-threadedge.c + (record_temporary_equivalences_from_stmts_at_dest): Make sure to + invalidate outputs from statements that do not produce useful + outputs for threading. + 2014-04-23 Venkataramanan Kumar * config/aarch64/aarch64.md (stack_protect_set, stack_protect_test) diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 126ad08300b3..62b07f4bc0da 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2014-04-23 Jeff Law + + PR tree-optimization/60902 + * gcc.target/i386/pr60902.c: New test. + 2014-04-23 Alex Velenko * gcc.target/aarch64/vdup_lane_1.c: New testcase. diff --git a/gcc/testsuite/gcc.target/i386/pr60902.c b/gcc/testsuite/gcc.target/i386/pr60902.c new file mode 100644 index 000000000000..b81dcd76f37a --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/pr60902.c @@ -0,0 +1,32 @@ +/* { dg-do run } */ +/* { dg-options "-O2" } */ +extern void abort (); +extern void exit (int); + +int x; + +foo() +{ + static int count; + count++; + if (count > 1) + abort (); +} + +static inline int +frob () +{ + int a; + __asm__ ("mov %1, %0\n\t" : "=r" (a) : "m" (x)); + x++; + return a; +} + +int +main () +{ + int i; + for (i = 0; i < 10 && frob () == 0; i++) + foo(); + exit (0); +} diff --git a/gcc/tree-ssa-threadedge.c b/gcc/tree-ssa-threadedge.c index c447b72c32f3..8a0103b1637f 100644 --- a/gcc/tree-ssa-threadedge.c +++ b/gcc/tree-ssa-threadedge.c @@ -387,7 +387,34 @@ record_temporary_equivalences_from_stmts_at_dest (edge e, && (gimple_code (stmt) != GIMPLE_CALL || gimple_call_lhs (stmt) == NULL_TREE || TREE_CODE (gimple_call_lhs (stmt)) != SSA_NAME)) - continue; + { + /* STMT might still have DEFS and we need to invalidate any known + equivalences for them. + + Consider if STMT is a GIMPLE_ASM with one or more outputs that + feeds a conditional inside a loop. We might derive an equivalence + due to the conditional. */ + tree op; + ssa_op_iter iter; + + if (backedge_seen) + FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_ALL_DEFS) + { + /* This call only invalidates equivalences created by + PHI nodes. This is by design to keep the cost of + of invalidation reasonable. */ + invalidate_equivalences (op, stack, src_map, dst_map); + + /* However, conditionals can imply values for real + operands as well. And those won't be recorded in the + maps. In fact, those equivalences may be recorded totally + outside the threading code. We can just create a new + temporary NULL equivalence here. */ + record_temporary_equivalence (op, NULL_TREE, stack); + } + + continue; + } /* The result of __builtin_object_size depends on all the arguments of a phi node. Temporarily using only one edge produces invalid