| Message ID | 53B3BA3B.8020705@mentor.com |
|---|---|
| State | New |
| Headers | show |
On 02/07/14 08:52, Tom de Vries wrote: > On 01-07-14 21:47, Jeff Law wrote: >> On 07/01/14 13:27, Tom de Vries wrote: >>> So my question is: is the combination of '&' and '+' supported ? If so, >>> what is the exact semantics ? If not, should we warn or give an error ? > > >> I don't think we can define any reasonable semantics for &+. My recommendation >> would be for this to be considered a hard error. >> > Why would this be any different in behaviour from use of operand tie constraints to early-clobber? In my view, it says that this operand is safe from the early-clobber limitation, but other operands are not and need to be in other registers. Eg op0 ("=&r") op1("0") op2("r") says that op1 must be the same register as op0, but op2 must be a different register, so A = A <op> B is ok, but A = A <op> A is not. R. > [ move discussion from gcc ml to gcc-patches ml ] > > Attached patch detects the combination of + and & constrains during genrecog, > and generates an error like this: > ... > /home/vries/gcc_versions/devel/src/gcc/config/aarch64/aarch64-simd.md:1020: > operand 0 has in-out reload, incompatible with earlyclobber > /home/vries/gcc_versions/devel/src/gcc/config/aarch64/aarch64-simd.md:1020: > operand 0 has in-out reload, incompatible with earlyclobber > /home/vries/gcc_versions/devel/src/gcc/config/aarch64/aarch64-simd.md:1020: > operand 0 has in-out reload, incompatible with earlyclobber > make[2]: *** [s-recog] Error 1 > ... > The error triggers three times, once for each mode iterator element. > > OK if x86_64 bootstrap succeeds ? > > Thanks, > - Tom > > > 0004-Don-t-allow-earlyclobber-modifier-with-read-write-mo.patch > > > 2014-07-02 Tom de Vries <tom@codesourcery.com> > > * genrecog.c (validate_pattern): Don't allow earlyclobber constraint > modifier with read/write constraint modifier. > > diff --git a/gcc/genrecog.c b/gcc/genrecog.c > index 457b59c..ad709ee 100644 > --- a/gcc/genrecog.c > +++ b/gcc/genrecog.c > @@ -481,6 +481,13 @@ validate_pattern (rtx pattern, rtx insn, rtx set, int set_code) > rtx_name[GET_CODE (insn)]); > } > > + if (constraints0 == '+' > + && strchr (XSTR (pattern, 2), '&') != NULL) > + error_with_line (pattern_lineno, > + "operand %d has in-out reload, incompatible with" > + " earlyclobber", > + XINT (pattern, 0)); > + > /* A MATCH_OPERAND that is a SET should have an output reload. */ > else if (set && constraints0) > { >
2014-07-02 Tom de Vries <tom@codesourcery.com> * genrecog.c (validate_pattern): Don't allow earlyclobber constraint modifier with read/write constraint modifier. diff --git a/gcc/genrecog.c b/gcc/genrecog.c index 457b59c..ad709ee 100644 --- a/gcc/genrecog.c +++ b/gcc/genrecog.c @@ -481,6 +481,13 @@ validate_pattern (rtx pattern, rtx insn, rtx set, int set_code) rtx_name[GET_CODE (insn)]); } + if (constraints0 == '+' + && strchr (XSTR (pattern, 2), '&') != NULL) + error_with_line (pattern_lineno, + "operand %d has in-out reload, incompatible with" + " earlyclobber", + XINT (pattern, 0)); + /* A MATCH_OPERAND that is a SET should have an output reload. */ else if (set && constraints0) { -- 1.9.1