On Tue, 23 Feb 2021, Tamar Christina wrote: > Hi Richi, > > The attached testcase ICEs due to a couple of issues. > In the testcase you have two SLP instances that share the majority of their > definition with each other. One tree defines a COMPLEX_MUL sequence and the > other tree a COMPLEX_FMA. > > The ice happens because: > > 1. the refcounts are wrong, in particular the FMA case doesn't correctly count > the references for the COMPLEX_MUL that it consumes. > > 2. when the FMA is created it incorrectly assumes it can just tear apart the > MUL > node that it's consuming. This is wrong and should only be done when there is > no more uses of the node, in which case the vector only pattern is no longer > relevant. > > To fix the last part the SLP only pattern reset code was moved into > vect_free_slp_tree which results in cleaner code. I also think it does belong > there since that function knows when there are no more uses of the node and so > the pattern should be unmarked, so when the the vectorizer is inspecting the > BB > it doesn't find the now invalid vector only patterns. > > The patch also clears the SLP_TREE_REPRESENTATIVE when stores are removed such > that we don't hit an error later trying to free the stmt_vec_info again. > > Lastly it also tweaks the results of whether a pattern has been detected or > not > to return true when another SLP instance has created a pattern that is only > used > by a different instance (due to the trees being unshared). > > Instead of ICEing this code now produces > > adrp x1, .LANCHOR0 > add x2, x1, :lo12:.LANCHOR0 > movi v1.2s, 0 > mov w0, 0 > ldr x4, [x1, #:lo12:.LANCHOR0] > ldrsw x3, [x2, 16] > ldr x1, [x2, 8] > ldrsw x2, [x2, 20] > ldr d0, [x4] > ldr d2, [x1, x3, lsl 3] > fcmla v2.2s, v0.2s, v0.2s, #0 > fcmla v2.2s, v0.2s, v0.2s, #90 > str d2, [x1, x3, lsl 3] > fcmla v1.2s, v0.2s, v0.2s, #0 > fcmla v1.2s, v0.2s, v0.2s, #90 > str d1, [x1, x2, lsl 3] > ret > > PS. This testcase actually shows that the codegen we get in these cases is not > optimal. It should generate a MUL + ADD instead MUL + FMA. > > But that's for GCC 12. > > Bootstrapped Regtested on aarch64-none-linux-gnu and no issues.
OK. Thanks, Richard. > Thanks, > Tamar > > gcc/ChangeLog: > > PR tree-optimization/99149 > * tree-vect-slp-patterns.c (vect_detect_pair_op): Don't recreate the > buffer. > (vect_slp_reset_pattern): Remove. > (complex_fma_pattern::matches): Remove call to vect_slp_reset_pattern. > (complex_mul_pattern::build, complex_fma_pattern::build, > complex_fms_pattern::build): Fix ref counts. > * tree-vect-slp.c (vect_free_slp_tree): Undo SLP only pattern relevancy > when node is being deleted. > (vect_match_slp_patterns_2): Correct result of cache hit on patterns. > (vect_schedule_slp): Invalidate SLP_TREE_REPRESENTATIVE of removed > stores. > * tree-vectorizer.c (vec_info::new_stmt_vec_info): Initialize value. > > gcc/testsuite/ChangeLog: > > PR tree-optimization/99149 > * g++.dg/vect/pr99149.cc: New test. > > --- inline copy of patch -- > diff --git a/gcc/testsuite/g++.dg/vect/pr99149.cc > b/gcc/testsuite/g++.dg/vect/pr99149.cc > new file mode 100755 > index > 0000000000000000000000000000000000000000..902a26f576fcc79d2802bec093668674cca1c84f > --- /dev/null > +++ b/gcc/testsuite/g++.dg/vect/pr99149.cc > @@ -0,0 +1,28 @@ > +/* { dg-do compile } */ > +/* { dg-additional-options "-w -O3 -march=armv8.3-a -fdump-tree-slp-all" { > target { aarch64*-*-* } } } */ > + > +class a { > + float b; > + float c; > + > +public: > + a(float d, float e) : b(d), c(e) {} > + a operator+(a d) { return a(b + d.b, c + d.c); } > + a operator*(a d) { return a(b * b - c * c, b * c + c * d.b); } > +}; > +int f, g; > +class { > + a *h; > + a *i; > + > +public: > + void j() { > + a k = h[0], l = i[g], m = k * i[f]; > + i[g] = l + m; > + i[f] = m; > + } > +} n; > +main() { n.j(); } > + > +/* { dg-final { scan-tree-dump-times "stmt.*COMPLEX_MUL" 1 "slp2" } } */ > +/* { dg-final { scan-tree-dump-times "stmt.*COMPLEX_FMA" 1 "slp2" } } */ > diff --git a/gcc/tree-vect-slp-patterns.c b/gcc/tree-vect-slp-patterns.c > index > f0817da9f622d22e3df2e30410d1cf610b4ffa1d..1e2769662a54229ab8e24390f97dfe206f17ab57 > 100644 > --- a/gcc/tree-vect-slp-patterns.c > +++ b/gcc/tree-vect-slp-patterns.c > @@ -407,9 +407,8 @@ vect_detect_pair_op (slp_tree node1, slp_tree node2, > lane_permutation_t &lanes, > > if (result != CMPLX_NONE && ops != NULL) > { > - ops->create (2); > - ops->quick_push (node1); > - ops->quick_push (node2); > + ops->safe_push (node1); > + ops->safe_push (node2); > } > return result; > } > @@ -1090,15 +1089,17 @@ complex_mul_pattern::build (vec_info *vinfo) > { > slp_tree node; > unsigned i; > + slp_tree newnode > + = vect_build_combine_node (this->m_ops[0], this->m_ops[1], > *this->m_node); > + SLP_TREE_REF_COUNT (this->m_ops[2])++; > + > FOR_EACH_VEC_ELT (SLP_TREE_CHILDREN (*this->m_node), i, node) > vect_free_slp_tree (node); > > /* First re-arrange the children. */ > SLP_TREE_CHILDREN (*this->m_node).reserve_exact (2); > SLP_TREE_CHILDREN (*this->m_node)[0] = this->m_ops[2]; > - SLP_TREE_CHILDREN (*this->m_node)[1] = > - vect_build_combine_node (this->m_ops[0], this->m_ops[1], *this->m_node); > - SLP_TREE_REF_COUNT (this->m_ops[2])++; > + SLP_TREE_CHILDREN (*this->m_node)[1] = newnode; > > /* And then rewrite the node itself. */ > complex_pattern::build (vinfo); > @@ -1133,18 +1134,6 @@ class complex_fma_pattern : public complex_pattern > } > }; > > -/* Helper function to "reset" a previously matched node and undo the changes > - made enough so that the node is treated as an irrelevant node. */ > - > -static inline void > -vect_slp_reset_pattern (slp_tree node) > -{ > - stmt_vec_info stmt_info = vect_orig_stmt (SLP_TREE_REPRESENTATIVE (node)); > - STMT_VINFO_IN_PATTERN_P (stmt_info) = false; > - STMT_SLP_TYPE (stmt_info) = pure_slp; > - SLP_TREE_REPRESENTATIVE (node) = stmt_info; > -} > - > /* Pattern matcher for trying to match complex multiply and accumulate > and multiply and subtract patterns in SLP tree. > If the operation matches then IFN is set to the operation it matched and > @@ -1208,15 +1197,6 @@ complex_fma_pattern::matches (complex_operation_t op, > if (!vect_pattern_validate_optab (ifn, vnode)) > return IFN_LAST; > > - /* FMA matched ADD + CMUL. During the matching of CMUL the > - stmt that starts the pattern is marked as being in a pattern, > - namely the CMUL. When replacing this with a CFMA we have to > - unmark this statement as being in a pattern. This is because > - vect_mark_pattern_stmts will only mark the current stmt as being > - in a pattern. Later on when the scalar stmts are examined the > - old statement which is supposed to be irrelevant will point to > - CMUL unless we undo the pattern relationship here. */ > - vect_slp_reset_pattern (node); > ops->truncate (0); > ops->create (3); > > @@ -1259,10 +1239,17 @@ complex_fma_pattern::recognize > (slp_tree_to_load_perm_map_t *perm_cache, > void > complex_fma_pattern::build (vec_info *vinfo) > { > + slp_tree node = SLP_TREE_CHILDREN (*this->m_node)[1]; > + > SLP_TREE_CHILDREN (*this->m_node).release (); > SLP_TREE_CHILDREN (*this->m_node).create (3); > SLP_TREE_CHILDREN (*this->m_node).safe_splice (this->m_ops); > > + SLP_TREE_REF_COUNT (this->m_ops[1])++; > + SLP_TREE_REF_COUNT (this->m_ops[2])++; > + > + vect_free_slp_tree (node); > + > complex_pattern::build (vinfo); > } > > @@ -1427,6 +1414,11 @@ complex_fms_pattern::build (vec_info *vinfo) > { > slp_tree node; > unsigned i; > + slp_tree newnode = > + vect_build_combine_node (this->m_ops[2], this->m_ops[3], *this->m_node); > + SLP_TREE_REF_COUNT (this->m_ops[0])++; > + SLP_TREE_REF_COUNT (this->m_ops[1])++; > + > FOR_EACH_VEC_ELT (SLP_TREE_CHILDREN (*this->m_node), i, node) > vect_free_slp_tree (node); > > @@ -1436,10 +1428,7 @@ complex_fms_pattern::build (vec_info *vinfo) > /* First re-arrange the children. */ > SLP_TREE_CHILDREN (*this->m_node).quick_push (this->m_ops[0]); > SLP_TREE_CHILDREN (*this->m_node).quick_push (this->m_ops[1]); > - SLP_TREE_CHILDREN (*this->m_node).quick_push ( > - vect_build_combine_node (this->m_ops[2], this->m_ops[3], *this->m_node)); > - SLP_TREE_REF_COUNT (this->m_ops[0])++; > - SLP_TREE_REF_COUNT (this->m_ops[1])++; > + SLP_TREE_CHILDREN (*this->m_node).quick_push (newnode); > > /* And then rewrite the node itself. */ > complex_pattern::build (vinfo); > diff --git a/gcc/tree-vect-slp.c b/gcc/tree-vect-slp.c > index > ea8a97b01c6371791ac66de3e1dabfedee69cb67..605873714a5cafaaf822f61f1f769f96b3876694 > 100644 > --- a/gcc/tree-vect-slp.c > +++ b/gcc/tree-vect-slp.c > @@ -146,6 +146,16 @@ vect_free_slp_tree (slp_tree node) > if (child) > vect_free_slp_tree (child); > > + /* If the node defines any SLP only patterns then those patterns are no > + longer valid and should be removed. */ > + stmt_vec_info rep_stmt_info = SLP_TREE_REPRESENTATIVE (node); > + if (rep_stmt_info && STMT_VINFO_SLP_VECT_ONLY_PATTERN (rep_stmt_info)) > + { > + stmt_vec_info stmt_info = vect_orig_stmt (rep_stmt_info); > + STMT_VINFO_IN_PATTERN_P (stmt_info) = false; > + STMT_SLP_TYPE (stmt_info) = STMT_SLP_TYPE (rep_stmt_info); > + } > + > delete node; > } > > @@ -2395,7 +2405,9 @@ vect_match_slp_patterns_2 (slp_tree *ref_node, vec_info > *vinfo, > slp_tree node = *ref_node; > bool found_p = false; > if (!node || visited->add (node)) > - return false; > + return node > + && SLP_TREE_REPRESENTATIVE (node) > + && STMT_VINFO_SLP_VECT_ONLY_PATTERN (SLP_TREE_REPRESENTATIVE (node)); > > slp_tree child; > FOR_EACH_VEC_ELT (SLP_TREE_CHILDREN (node), i, child) > @@ -6451,6 +6463,11 @@ vect_schedule_slp (vec_info *vinfo, vec<slp_instance> > slp_instances) > store_info = vect_orig_stmt (store_info); > /* Free the attached stmt_vec_info and remove the stmt. */ > vinfo->remove_stmt (store_info); > + > + /* Invalidate SLP_TREE_REPRESENTATIVE in case we released it > + to not crash in vect_free_slp_tree later. */ > + if (SLP_TREE_REPRESENTATIVE (root) == store_info) > + SLP_TREE_REPRESENTATIVE (root) = NULL; > } > } > } > diff --git a/gcc/tree-vectorizer.c b/gcc/tree-vectorizer.c > index > 5b45df3a4e00266b7530eb4da6985f0d940cb05b..63ba594f2276850a00fc372072d98326891f19e6 > 100644 > --- a/gcc/tree-vectorizer.c > +++ b/gcc/tree-vectorizer.c > @@ -695,6 +695,7 @@ vec_info::new_stmt_vec_info (gimple *stmt) > STMT_VINFO_REDUC_FN (res) = IFN_LAST; > STMT_VINFO_REDUC_IDX (res) = -1; > STMT_VINFO_SLP_VECT_ONLY (res) = false; > + STMT_VINFO_SLP_VECT_ONLY_PATTERN (res) = false; > STMT_VINFO_VEC_STMTS (res) = vNULL; > > if (is_a <loop_vec_info> (this) > > > -- Richard Biener <rguent...@suse.de> SUSE Software Solutions Germany GmbH, Maxfeldstrasse 5, 90409 Nuernberg, Germany; GF: Felix Imendörffer; HRB 36809 (AG Nuernberg)