Hi!
SCEV can analyze not just integral/pointer IVs, but (scalar) float ones as
well. Calling build_int_cst on such types results in ICE, build_zero_cst
works. Though the loop invariant PHI IVs, if we represent them as using
+0.0 step, aren't correct if honoring signed zeros, as + 0.0 will make
a +0.0 out of -0.0.
Bootstrapped/regtested on {x86_64,i686,powerpc64{,le}}-linux, ok for trunk?
2019-01-22 Jakub Jelinek <ja...@redhat.com>
PR tree-optimization/88964
* gimple-loop-interchange.cc (loop_cand::analyze_induction_var): Use
build_zero_cst instead of build_int_cst. Return false for loop
invariants which honor signed zeros.
* gfortran.dg/pr88964.f90: New test.
--- gcc/gimple-loop-interchange.cc.jj 2019-01-01 12:37:17.416970701 +0100
+++ gcc/gimple-loop-interchange.cc 2019-01-22 11:34:42.303796570 +0100
@@ -688,11 +688,16 @@ loop_cand::analyze_induction_var (tree v
/* Var is loop invariant, though it's unlikely to happen. */
if (tree_does_not_contain_chrecs (chrec))
{
+ /* Punt on floating point invariants if honoring signed zeros,
+ representing that as + 0.0 would change the result if init
+ is -0.0. */
+ if (HONOR_SIGNED_ZEROS (chrec))
+ return false;
struct induction *iv = XCNEW (struct induction);
iv->var = var;
iv->init_val = init;
iv->init_expr = chrec;
- iv->step = build_int_cst (TREE_TYPE (chrec), 0);
+ iv->step = build_zero_cst (TREE_TYPE (chrec));
m_inductions.safe_push (iv);
return true;
}
--- gcc/testsuite/gfortran.dg/pr88964.f90.jj 2019-01-22 11:54:46.046154065
+0100
+++ gcc/testsuite/gfortran.dg/pr88964.f90 2019-01-22 11:54:23.172526590
+0100
@@ -0,0 +1,57 @@
+! PR tree-optimization/88964
+! { dg-do compile }
+! { dg-options "-O3 -fno-tree-forwprop --param
sccvn-max-alias-queries-per-access=1" }
+
+MODULE pr88964
+ INTEGER, PARAMETER :: dp=8
+ REAL(KIND=dp) :: p, q, o
+CONTAINS
+ SUBROUTINE foo(a,b,c,f,h)
+ IMPLICIT NONE
+ INTEGER :: a, b, c
+ REAL(KIND=dp) :: f(b*c), h(a*c)
+ CALL bar(h)
+ CALL baz(f)
+ CALL qux(h)
+ END SUBROUTINE foo
+ SUBROUTINE bar(h)
+ IMPLICIT NONE
+ REAL(KIND=dp) :: h(1*1)
+ INTEGER :: r, s, t, u
+ DO u = 1,3
+ DO t = 1,1
+ DO s = 1,3
+ DO r = 1,1
+ h((t-1)*1+r) = h((t-1)*1+r)-p*o
+ END DO
+ END DO
+ END DO
+ END DO
+ END SUBROUTINE bar
+ SUBROUTINE baz(f)
+ IMPLICIT NONE
+ REAL(KIND=dp) :: f(3*1)
+ INTEGER :: s, t, u
+ DO u = 1,4
+ DO t = 1,1
+ DO s = 1,3
+ f((t-1)*3+s) = f((t-1)*3+s) - q
+ END DO
+ END DO
+ END DO
+ END SUBROUTINE baz
+ SUBROUTINE qux(h)
+ IMPLICIT NONE
+ REAL(KIND=dp) :: h(1*1)
+ INTEGER :: r, s, t, u
+ DO u = 1,5
+ DO t = 1,1
+ DO s = 1,3
+ DO r = 1,1
+ h((t-1)*1+r) = h((t-1)*1+r)-p*o
+ END DO
+ END DO
+ END DO
+ END DO
+ END SUBROUTINE qux
+END MODULE pr88964
Jakub
