Hi All,
As shown in PR115936 SCEV and IVOPTS create an invalidate IV when the IV is
a pointer type:
ivtmp.39_65 = ivtmp.39_59 + 0B;
where the IVs are DI mode and the offset is a pointer.
This comes from this weird candidate:
Candidate 8:
Var befor: ivtmp.39_59
Var after: ivtmp.39_65
Incr POS: before exit test
IV struct:
Type: sizetype
Base: 0
Step: 0B
Biv: N
Overflowness wrto loop niter: No-overflow
This IV was always created just ended up not being used.
This is created by SCEV.
simple_iv_with_niters in the case where no CHREC is found creates an IV with
base == ev, offset == 0;
however in this case EV is a POINTER_PLUS_EXPR and so the type is a pointer.
it ends up creating an unusable expression.
However IVOPTS also has code to refold expression in case the IV is a pointer.
For most cases it uses basetype to fold both operand but the 0 case it ommitted
it. This leads to us creating a PLUS expression with mismatched types.
This fixes that bug as well.
Bootstrapped Regtested on aarch64-none-linux-gnu,
x86_64-pc-linux-gnu -m32, -m64 and no issues.
Ok for master?
Thanks,
Tamar
gcc/ChangeLog:
PR tree-optimization/115936
* tree-scalar-evolution.cc (simple_iv_with_niters): Use sizetype for
pointers.
* tree-ssa-loop-ivopts.cc (add_iv_candidate_for_use): Use same type for
both operands.
---
diff --git a/gcc/tree-scalar-evolution.cc b/gcc/tree-scalar-evolution.cc
index
5aa95a2497a317f9b43408ce78a2d50c20151314..abb2bad777375889d6c980b54d60699672fd5742
100644
--- a/gcc/tree-scalar-evolution.cc
+++ b/gcc/tree-scalar-evolution.cc
@@ -3243,7 +3243,11 @@ simple_iv_with_niters (class loop *wrto_loop, class loop
*use_loop,
if (tree_does_not_contain_chrecs (ev))
{
iv->base = ev;
- iv->step = build_int_cst (TREE_TYPE (ev), 0);
+ tree ev_type = TREE_TYPE (ev);
+ if (POINTER_TYPE_P (ev_type))
+ ev_type = sizetype;
+
+ iv->step = build_int_cst (ev_type, 0);
iv->no_overflow = true;
return true;
}
diff --git a/gcc/tree-ssa-loop-ivopts.cc b/gcc/tree-ssa-loop-ivopts.cc
index
c3218a3e8eedbb8d0a7f14c01eeb069cb6024c29..fe130541526e74fb80fee633f6c96b41437aa1c1
100644
--- a/gcc/tree-ssa-loop-ivopts.cc
+++ b/gcc/tree-ssa-loop-ivopts.cc
@@ -3529,7 +3529,8 @@ add_iv_candidate_for_use (struct ivopts_data *data,
struct iv_use *use)
basetype = TREE_TYPE (iv->base);
if (POINTER_TYPE_P (basetype))
basetype = sizetype;
- record_common_cand (data, build_int_cst (basetype, 0), iv->step, use);
+ record_common_cand (data, build_int_cst (basetype, 0),
+ fold_convert (basetype, iv->step), use);
/* Compare the cost of an address with an unscaled index with the cost of
an address with a scaled index and add candidate if useful. */
--
diff --git a/gcc/tree-scalar-evolution.cc b/gcc/tree-scalar-evolution.cc
index 5aa95a2497a317f9b43408ce78a2d50c20151314..abb2bad777375889d6c980b54d60699672fd5742 100644
--- a/gcc/tree-scalar-evolution.cc
+++ b/gcc/tree-scalar-evolution.cc
@@ -3243,7 +3243,11 @@ simple_iv_with_niters (class loop *wrto_loop, class loop *use_loop,
if (tree_does_not_contain_chrecs (ev))
{
iv->base = ev;
- iv->step = build_int_cst (TREE_TYPE (ev), 0);
+ tree ev_type = TREE_TYPE (ev);
+ if (POINTER_TYPE_P (ev_type))
+ ev_type = sizetype;
+
+ iv->step = build_int_cst (ev_type, 0);
iv->no_overflow = true;
return true;
}
diff --git a/gcc/tree-ssa-loop-ivopts.cc b/gcc/tree-ssa-loop-ivopts.cc
index c3218a3e8eedbb8d0a7f14c01eeb069cb6024c29..fe130541526e74fb80fee633f6c96b41437aa1c1 100644
--- a/gcc/tree-ssa-loop-ivopts.cc
+++ b/gcc/tree-ssa-loop-ivopts.cc
@@ -3529,7 +3529,8 @@ add_iv_candidate_for_use (struct ivopts_data *data, struct iv_use *use)
basetype = TREE_TYPE (iv->base);
if (POINTER_TYPE_P (basetype))
basetype = sizetype;
- record_common_cand (data, build_int_cst (basetype, 0), iv->step, use);
+ record_common_cand (data, build_int_cst (basetype, 0),
+ fold_convert (basetype, iv->step), use);
/* Compare the cost of an address with an unscaled index with the cost of
an address with a scaled index and add candidate if useful. */
