https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84128
Bug ID: 84128
Summary: i686: Stack spilling in -fstack-clash-protection
prologue neglects %esp change
Product: gcc
Version: 8.0
Status: UNCONFIRMED
Keywords: wrong-code
Severity: normal
Priority: P3
Component: target
Assignee: law at redhat dot com
Reporter: fw at gcc dot gnu.org
Target Milestone: ---
Target: i686
Created attachment 43291
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=43291&action=edit
Reproducer
The attached test case (compile with -m32 -march=i686 -mtune=generic
-fstack-clash-protection -O2) shows that %eax is popped off the stack in the
stack-clash protection prologue after %esp has been moved:
f1:
.LFB0:
.cfi_startproc
pushl %eax
.cfi_def_cfa_offset 8
.cfi_offset 0, -8
leal -32768(%esp), %eax
.cfi_def_cfa 0, 32776
.LPSRL0:
subl $4096, %esp
orl $0, (%esp)
cmpl %eax, %esp
jne .LPSRL0
.cfi_def_cfa_register 4
subl $12, %esp
.cfi_def_cfa_offset 32788
popl %eax
Is this a missing stack tie?
Seen with trunk@257087. Test case reduced from a miscompilation of pcre2.
