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author | Xavier Leroy <xavier.leroy@inria.fr> | 2016-07-08 15:44:46 +0200 |
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committer | Xavier Leroy <xavier.leroy@inria.fr> | 2016-07-08 15:44:46 +0200 |
commit | 4c7650c3eaf4dfbe5971864bf084e76f844051ee (patch) | |
tree | 32b5deb84cb3fd36f4baada8eed4ce108aed9599 /common | |
parent | e73d5db97cdb22cce2ee479469f62af3c4b6264a (diff) | |
download | compcert-4c7650c3eaf4dfbe5971864bf084e76f844051ee.tar.gz compcert-4c7650c3eaf4dfbe5971864bf084e76f844051ee.zip |
Unwanted partial constant propagation in 64-bit integer arguments to builtins
Here are two examples that cause an internal error in Asmexpand.ml:
volatile long long x; void f(unsigned int i) { x = i; }
unsigned g(unsigned i) { return __builtin_clzll(i); }
The argument "i" to builtin volatile store or __builtin_clzll is turned into a BA_splitlong(BA_int 0, BA <variable i>), which Asmexpand.ml doesn't know how to handle.
The fix (in AST.builtin_arg_ok) is to prevent this 'optimization' for all builtins except those of the "OK_all" kind, i.e. __builtin_annot.
Regression tests were added and tested on IA32. Need to retest on ARM and PowerPC.
Diffstat (limited to 'common')
-rw-r--r-- | common/AST.v | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/common/AST.v b/common/AST.v index 0b524eb8..ae7178f4 100644 --- a/common/AST.v +++ b/common/AST.v @@ -684,7 +684,7 @@ Inductive builtin_arg_constraint : Type := Definition builtin_arg_ok (A: Type) (ba: builtin_arg A) (c: builtin_arg_constraint) := match ba, c with - | (BA _ | BA_splitlong _ _), _ => true + | (BA _ | BA_splitlong (BA _) (BA _)), _ => true | (BA_int _ | BA_long _ | BA_float _ | BA_single _), OK_const => true | BA_addrstack _, (OK_addrstack | OK_addrany) => true | BA_addrglobal _ _, (OK_addrglobal | OK_addrany) => true |