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From: "trippels at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug rtl-optimization/65805] [5/6 Regression] Chromium gets miscompiled
Date: Sun, 19 Apr 2015 17:39:00 -0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65805

--- Comment #3 from Markus Trippelsdorf <trippels at gcc dot gnu.org> ---
It is clearer to see the issue if one compiles the whole file with
-fno-lra-remat:

markus@x4 Release % g++ -S -fno-lra-remat -fPIC -fvisibility=hidden -pthread
-march=x86-64 -O2 -fno-exceptions -fno-rtti -std=gnu++11 -Wall -c file_util.ii
-o out_good
markus@x4 Release % g++ -S -fPIC -fvisibility=hidden -pthread -march=x86-64 -O2
-fno-exceptions -fno-rtti -std=gnu++11 -Wall -c file_util.ii -o out_bad  
markus@x4 Release % diff -u out_good out_bad
...
@@ -4616,7 +4616,7 @@
        pushq   %rbp
        .cfi_def_cfa_offset 128
        movl    20(%rsp), %edx
-       movq    24(%rsp), %rdi
+       leaq    64(%rsp), %rdi
        call   
_ZN10extensions9Extension6CreateERKN4base8FilePathENS_8Manifest8LocationERKNS1_15DictionaryValueEiRKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEEPSF_@PLT
        movq    32(%rsp), %r13
        popq    %rax

When I change "leaq 64(%rsp), %rdi" back to "movq 24(%rsp), %rdi"
chromium runs fine.