[Bug target/79671] [7 Regression] mapnik miscompilation on armv7hl since r235622

["bernd.edlinger at hotmail dot de" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79671

Bernd Edlinger <bernd.edlinger at hotmail dot de> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |bernd.edlinger at hotmail dot de

--- Comment #12 from Bernd Edlinger <bernd.edlinger at hotmail dot de> ---
Hi,

I don't know if it helps, but on the assembler level there are only two
instructions that need to be moved to make the test case pass:

diff -u rh1422456-orig.s rh1422456.s
--- rh1422456-orig.s    2017-02-26 22:46:30.068919262 +0100
+++ rh1422456.s 2017-02-26 22:46:56.445920712 +0100
@@ -2046,10 +2046,10 @@
        ldr     ip, [r4, #100]
        add     lr, sp, #52
        movw    r3,
#:lower16:_ZZN5boost9function4IbRN9__gnu_cxx17__normal_iteratorIPKcNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEEEERKSB_RNS_6spirit7contextINS_6fusion4consIRSA_NSH_4nil_EEENSH_6vectorIJEEEEERKNSF_2qi10char_classINSF_3tag9char_codeINSS_5spaceENSF_13char_encoding13standard_wideEEEEEE9assign_toINSQ_6detail13parser_binderINSQ_4plusINSQ_10differenceINSR_INST_INSS_5char_ESW_EEEENSQ_12literal_charINSV_8standardELb1ELb0EEEEEEEN4mpl_5bool_ILb1EEEEEEEvT_E13stored_vtable
+       strb    r6, [sp, #293]
        ldm     r5, {r0, r1, r2}
        cmp     ip, #0
        movt    r3,
#:upper16:_ZZN5boost9function4IbRN9__gnu_cxx17__normal_iteratorIPKcNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEEEERKSB_RNS_6spirit7contextINS_6fusion4consIRSA_NSH_4nil_EEENSH_6vectorIJEEEEERKNSF_2qi10char_classINSF_3tag9char_codeINSS_5spaceENSF_13char_encoding13standard_wideEEEEEE9assign_toINSQ_6detail13parser_binderINSQ_4plusINSQ_10differenceINSR_INST_INSS_5char_ESW_EEEENSQ_12literal_charINSV_8standardELb1ELb0EEEEEEEN4mpl_5bool_ILb1EEEEEEEvT_E13stored_vtable
-       strb    r6, [sp, #293]
        orr     r3, r3, #1
        str     r7, [sp, #288]
        str     r3, [sp, #48]
@@ -2062,10 +2062,10 @@
        ldr     ip, [r4, #144]
        add     lr, sp, #68
        movw    r3,
#:lower16:_ZZN5boost9function4IbRN9__gnu_cxx17__normal_iteratorIPKcNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEEEERKSB_RNS_6spirit7contextINS_6fusion4consIRSA_NSH_4nil_EEENSH_6vectorIJEEEEERKNSF_11unused_typeEE9assign_toINSF_2qi6detail13parser_binderINSV_16lexeme_directiveINSV_4plusINSV_10differenceINSV_10char_classINSF_3tag9char_codeINS12_5char_ENSF_13char_encoding13standard_wideEEEEENSV_12literal_charINS15_8standardELb1ELb0EEEEEEEEEN4mpl_5bool_ILb1EEEEEEEvT_E13stored_vtable
+       strb    r6, [sp, #293]
        ldm     r5, {r0, r1, r2}
        cmp     ip, #0
        movt    r3,
#:upper16:_ZZN5boost9function4IbRN9__gnu_cxx17__normal_iteratorIPKcNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEEEERKSB_RNS_6spirit7contextINS_6fusion4consIRSA_NSH_4nil_EEENSH_6vectorIJEEEEERKNSF_11unused_typeEE9assign_toINSF_2qi6detail13parser_binderINSV_16lexeme_directiveINSV_4plusINSV_10differenceINSV_10char_classINSF_3tag9char_codeINS12_5char_ENSF_13char_encoding13standard_wideEEEEENSV_12literal_charINS15_8standardELb1ELb0EEEEEEEEEN4mpl_5bool_ILb1EEEEEEEvT_E13stored_vtable
-       strb    r6, [sp, #293]
        orr     r3, r3, #1
        str     r7, [sp, #288]
        str     r3, [sp, #64]

=> r5 = sp+292, so strb and ldm overlap.
In the reload pass I can find the sp+293 mem rtx:

(insn 593 1693 598 67 (parallel [
            (set (reg:SI 0 r0)
                (mem/c:SI (reg/f:SI 5 r5 [680]) [19 MEM[(struct
function4D.541978 *)&D.615141].D.542200.functorD.466600+0 S4 A32]))
            (set (reg:SI 1 r1)
                (mem/c:SI (plus:SI (reg/f:SI 5 r5 [680])
                        (const_int 4 [0x4])) [19 MEM[(struct function4D.541978
*)&D.615141].D.542200.functorD.466600+4 S4 A32]))
            (set (reg:SI 2 r2)
                (mem/c:SI (plus:SI (reg/f:SI 5 r5 [680])
                        (const_int 8 [0x8])) [19 MEM[(struct function4D.541978
*)&D.615141].D.542200.functorD.466600+8 S4 A32]))
        ]) "rh1422456.cc":151826 364 {*ldm3_}
     (nil))
(insn 598 593 586 67 (set (reg:CC 100 cc)
        (compare:CC (reg/f:SI 12 ip [orig:181 _251 ] [181])
            (const_int 0 [0]))) "rh1422456.cc":151823 196 {*arm_cmpsi_insn}
     (nil))
(insn 586 598 591 67 (set (mem/c:QI (plus:SI (reg/f:SI 13 sp)
                (const_int 293 [0x125])) [101 MEM[(struct parser_binderD.572000
*)&D.615141 + 5B]+0 S1 A8])
        (reg:QI 6 r6 [493])) 192 {*arm_movqi_insn}
     (nil))

... and: 

(insn 878 1691 883 99 (parallel [
            (set (reg:SI 0 r0)
                (mem/c:SI (reg/f:SI 5 r5 [680]) [19 MEM[(struct
function4D.546780 *)&D.615194].D.547000.functorD.466600+0 S4 A32]))
            (set (reg:SI 1 r1)
                (mem/c:SI (plus:SI (reg/f:SI 5 r5 [680])
                        (const_int 4 [0x4])) [19 MEM[(struct function4D.546780
*)&D.615194].D.547000.functorD.466600+4 S4 A32]))
            (set (reg:SI 2 r2)
                (mem/c:SI (plus:SI (reg/f:SI 5 r5 [680])
                        (const_int 8 [0x8])) [19 MEM[(struct function4D.546780
*)&D.615194].D.547000.functorD.466600+8 S4 A32]))
        ]) "rh1422456.cc":151826 364 {*ldm3_}
     (nil))
(insn 883 878 871 99 (set (reg:CC 100 cc)
        (compare:CC (reg/f:SI 12 ip [orig:180 _249 ] [180])
            (const_int 0 [0]))) "rh1422456.cc":151823 196 {*arm_cmpsi_insn}
     (nil))
(insn 871 883 876 99 (set (mem/c:QI (plus:SI (reg/f:SI 13 sp)
                (const_int 293 [0x125])) [105 MEM[(struct parser_binderD.573224
*)&D.615194 + 5B]+0 S1 A8])
        (reg:QI 6 r6 [564])) 192 {*arm_movqi_insn}
     (nil))