On Wed, Jan 16, 2013 at 4:57 PM, Richard Biener <rguent...@suse.de> wrote:
>
> This fixes PR3713 by properly propagating ->has_constants in SCCVN.
> With that we are able to simplify (unsigned) Bar & 1 properly.
> Only copyprop later turns the call into a direct one though,
> so I'm testing the important fact - that Bar is inlined and eliminated
> by IPA inlining.
>
> Bootstrapped on x86_64-unknown-linux-gnu, testing in progress.
>
> Unless this is somehow a regression (which I doubt) this has to
> wait for stage1 (even though it's pretty safe and at most exposes
> existing bugs in SCCVN).
Committed as r196771.
Richard.
> Richard.
>
> 2013-01-16 Richard Biener <rguent...@suse.de>
>
> PR tree-optimization/3713
> * tree-ssa-sccvn.c (visit_copy): Simplify. Always propagate
> has_constants and expr.
> (stmt_has_constants): Properly valueize SSA names when deciding
> whether the stmt has constants.
>
> * g++.dg/ipa/devirt-11.C: New testcase.
>
> Index: gcc/tree-ssa-sccvn.c
> ===================================================================
> *** gcc/tree-ssa-sccvn.c (revision 195240)
> --- gcc/tree-ssa-sccvn.c (working copy)
> *************** static tree valueize_expr (tree expr);
> *** 2653,2670 ****
> static bool
> visit_copy (tree lhs, tree rhs)
> {
> - /* Follow chains of copies to their destination. */
> - while (TREE_CODE (rhs) == SSA_NAME
> - && SSA_VAL (rhs) != rhs)
> - rhs = SSA_VAL (rhs);
> -
> /* The copy may have a more interesting constant filled expression
> (we don't, since we know our RHS is just an SSA name). */
> ! if (TREE_CODE (rhs) == SSA_NAME)
> ! {
> ! VN_INFO (lhs)->has_constants = VN_INFO (rhs)->has_constants;
> ! VN_INFO (lhs)->expr = VN_INFO (rhs)->expr;
> ! }
>
> return set_ssa_val_to (lhs, rhs);
> }
> --- 2653,2665 ----
> static bool
> visit_copy (tree lhs, tree rhs)
> {
> /* The copy may have a more interesting constant filled expression
> (we don't, since we know our RHS is just an SSA name). */
> ! VN_INFO (lhs)->has_constants = VN_INFO (rhs)->has_constants;
> ! VN_INFO (lhs)->expr = VN_INFO (rhs)->expr;
> !
> ! /* And finally valueize. */
> ! rhs = SSA_VAL (rhs);
>
> return set_ssa_val_to (lhs, rhs);
> }
> *************** expr_has_constants (tree expr)
> *** 3063,3087 ****
> static bool
> stmt_has_constants (gimple stmt)
> {
> if (gimple_code (stmt) != GIMPLE_ASSIGN)
> return false;
>
> switch (get_gimple_rhs_class (gimple_assign_rhs_code (stmt)))
> {
> ! case GIMPLE_UNARY_RHS:
> ! return is_gimple_min_invariant (gimple_assign_rhs1 (stmt));
>
> case GIMPLE_BINARY_RHS:
> ! return (is_gimple_min_invariant (gimple_assign_rhs1 (stmt))
> ! || is_gimple_min_invariant (gimple_assign_rhs2 (stmt)));
> ! case GIMPLE_TERNARY_RHS:
> ! return (is_gimple_min_invariant (gimple_assign_rhs1 (stmt))
> ! || is_gimple_min_invariant (gimple_assign_rhs2 (stmt))
> ! || is_gimple_min_invariant (gimple_assign_rhs3 (stmt)));
> case GIMPLE_SINGLE_RHS:
> /* Constants inside reference ops are rarely interesting, but
> it can take a lot of looking to find them. */
> ! return is_gimple_min_invariant (gimple_assign_rhs1 (stmt));
> default:
> gcc_unreachable ();
> }
> --- 3058,3095 ----
> static bool
> stmt_has_constants (gimple stmt)
> {
> + tree tem;
> +
> if (gimple_code (stmt) != GIMPLE_ASSIGN)
> return false;
>
> switch (get_gimple_rhs_class (gimple_assign_rhs_code (stmt)))
> {
> ! case GIMPLE_TERNARY_RHS:
> ! tem = gimple_assign_rhs3 (stmt);
> ! if (TREE_CODE (tem) == SSA_NAME)
> ! tem = SSA_VAL (tem);
> ! if (is_gimple_min_invariant (tem))
> ! return true;
> ! /* Fallthru. */
>
> case GIMPLE_BINARY_RHS:
> ! tem = gimple_assign_rhs2 (stmt);
> ! if (TREE_CODE (tem) == SSA_NAME)
> ! tem = SSA_VAL (tem);
> ! if (is_gimple_min_invariant (tem))
> ! return true;
> ! /* Fallthru. */
> !
> case GIMPLE_SINGLE_RHS:
> /* Constants inside reference ops are rarely interesting, but
> it can take a lot of looking to find them. */
> ! case GIMPLE_UNARY_RHS:
> ! tem = gimple_assign_rhs1 (stmt);
> ! if (TREE_CODE (tem) == SSA_NAME)
> ! tem = SSA_VAL (tem);
> ! return is_gimple_min_invariant (tem);
> !
> default:
> gcc_unreachable ();
> }
> Index: gcc/testsuite/g++.dg/ipa/devirt-11.C
> ===================================================================
> *** gcc/testsuite/g++.dg/ipa/devirt-11.C (revision 0)
> --- gcc/testsuite/g++.dg/ipa/devirt-11.C (working copy)
> ***************
> *** 0 ****
> --- 1,22 ----
> + // { dg-do compile }
> + // { dg-options "-std=c++11 -O -fdump-ipa-inline" }
> +
> + class Foo
> + {
> + public:
> + void Bar() const
> + {
> + __builtin_puts ("Howdy!");
> + }
> + };
> +
> + int main()
> + {
> + Foo x;
> + auto y = &Foo::Bar;
> + (x.*y)();
> + return 0;
> + }
> +
> + // { dg-final { scan-ipa-dump "Inlined 1 calls, eliminated 1 functions"
> "inline" } }
> + // { dg-final { cleanup-ipa-dump "inline" } }
