[Bug tree-optimization/122686] [16 Regression] 521.wrf_r build hang on GNR with -Ofast -march=native -flto

[haochen.jiang at intel dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122686

--- Comment #15 from Haochen Jiang <haochen.jiang at intel dot com> ---
After the patch, it stuck at here:

;; Generating RTL for gimple basic block 17
Swap operands in stmt:
ivtmp.896_2513 = _2615 + _2616;
Cost left opnd=0, right opnd=1
 Registering value_relation (_2546 pe64 _139) (bb10) at _2546 = (unsigned long)
_139;

;; ivtmp.896_2513 = _2616 + _2615;

(insn 411 410 412 (parallel [
            (set (reg:DI 1333 [ _2616 ])
                (ashift:DI (reg:DI 1224 [ ivtmp.906 ])
                    (const_int 2 [0x2])))
            (clobber (reg:CC 17 flags))
        ]) -1
     (nil))

(insn 412 411 0 (parallel [
            (set (reg:DI 1204 [ ivtmp.896 ])
                (plus:DI (reg:DI 1333 [ _2616 ])
                    (reg:DI 1236 [ _2615 ])))
            (clobber (reg:CC 17 flags))
        ]) -1
     (nil))

;; _2524 = (int) _2523;

(insn 413 412 0 (parallel [
            (set (reg:SI 1207 [ _2524 ])
                (plus:SI (reg:SI 115 [ _18

Before the patch:

;; Generating RTL for gimple basic block 17

;;

(code_label 409 407 410 95 (nil) [0 uses])

(note 410 409 0 NOTE_INSN_BASIC_BLOCK)

;; if (_18 < _19)

(insn 411 410 412 (set (reg:CCGC 17 flags)
        (compare:CCGC (reg:SI 115 [ _18 ])
            (reg:SI 116 [ _19 ]))) "module_polarfft.fppized.f90":388:13 discrim
1 -1
     (nil))

(jump_insn 412 411 0 (set (pc)
        (if_then_else (ge (reg:CCGC 17 flags)
                (const_int 0 [0]))
            (label_ref 0)
            (pc))) "module_polarfft.fppized.f90":388:13 discrim 1 -1
     (int_list:REG_BR_PROB 955630225 (nil)))