https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68379
Bug ID: 68379
Summary: [6 Regression] BB vectorization: definition in block
13 follows the use for SSA_NAME
Product: gcc
Version: 6.0
Status: UNCONFIRMED
Keywords: wrong-code
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: rguenth at gcc dot gnu.org
Target Milestone: ---
Target: aarch64
! { dg-do compile }
! { dg-additional-options "-Ofast" }
! { dg-additional-options "-mavx" { target x86_64-*-* i?86-*-* } }
SUBROUTINE PASSB4 (IDO,L1,CC,CH,WA1,WA2,WA3)
IMPLICIT REAL(4) (A-H, O-Z)
DIMENSION CC(IDO,4,L1) ,CH(IDO,L1,4) ,&
WA1(*) ,WA2(*) ,WA3(*)
102 DO 104 K=1,L1
DO 103 I=2,IDO,2
TI1 = CC(I,1,K)-CC(I,3,K)
TI2 = CC(I,1,K)+CC(I,3,K)
TI3 = CC(I,2,K)+CC(I,4,K)
TR2 = CC(I-1,1,K)+CC(I-1,3,K)
TI4 = CC(I-1,2,K)-CC(I-1,4,K)
TR3 = CC(I-1,2,K)+CC(I-1,4,K)
CH(I-1,K,1) = TR2+TR3
CH(I,K,1) = TI2+TI3
CI4 = TI1-TI4
CH(I-1,K,4) = CI4
CH(I,K,4) = CI4
103 CONTINUE
104 CONTINUE
RETURN
END
on aarch64-linux ICEs with
vect-9.f90:5:0:
SUBROUTINE PASSB4 (IDO,L1,CC,CH,WA1,WA2,WA3)
Error: definition in block 11 follows the use
for SSA_NAME: _54 in statement:
vectp.20_198 = &*cc_36(D)[_54];
Breakpoint 2, internal_error (gmsgid=0x1718ff4 "verify_ssa failed")
which is because when we vectorize
vect-9.f90:10:0: note: node
vect-9.f90:10:0: note: stmt 0 _37 = *cc_36(D)[_35];
vect-9.f90:10:0: note: stmt 1 _37 = *cc_36(D)[_35];
the interleaving with _55 = *cc_36(D)[_54]; and a permutation of { 1 1 } will
cause us to base the reference off a pointer to a ref that does not
participate in the SLP node and thus is not considered when we look for
the insertion place with vect_find_last_scalar_stmt_in_slp.
