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[Bug rtl-optimization/59535] [4.9 regression] -Os code size regressions for Thumb1/Thumb2 with LRA
- From: "rearnsha at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Fri, 03 Jan 2014 14:43:58 +0000
- Subject: [Bug rtl-optimization/59535] [4.9 regression] -Os code size regressions for Thumb1/Thumb2 with LRA
- Auto-submitted: auto-generated
- References: <bug-59535-4 at http dot gcc dot gnu dot org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59535
--- Comment #15 from Richard Earnshaw <rearnsha at gcc dot gnu.org> ---
Another testcase where the thumb1 code is poor is
gcc.c-torture/execute/pr28982b.c
With LRA we often get sequences such as:
mov r3, sp
ldr r2, .L8+16
add r3, r3, r2 // r2 dead.
str r0, [r3]
Instead of:
ldr r2, .L8+16
add r2, r2, sp
str r0, [r2]
Which is both shorter and needs fewer registers.