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gcc "-fipa-pure-const" optimization
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s.diff
--- a1.s 2013-04-08 14:46:49.996856646 +0200
+++ a2.s 2013-04-08 14:46:23.800190673 +0200
@@ -91,7 +91,9 @@
movl $.LC0, %edi
movl $0, %eax
call printf
- movl %ebx, %esi
+ movl $0, %eax
+ call foo
+ movl %eax, %esi
movl $.LC1, %edi
movl $0, %eax
call printf
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soimort commented Apr 8, 2013

Regarding https://gist.github.com/innocentim/5335682:

compile with

$ gcc -O1 -o a1.s -S a.c

and

$ gcc -O1 -fno-ipa-pure-const -o a2.s -S a.c

$ diff -u a1.s a2.s

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