This adds MXCSR to the set of recognized registers for X86 targets and updates the instructions that read or write it. I do not intend for all of the various floating point instructions that implicitly use the control bits or update the status bits of this register to ever have that usage modeled by default. However, when constrained floating point modes (such as strict FP exception status modeling or dynamic rounding modes) are enabled, implicit use/def information for MXCSR will be added to those instructions.
Until those additional updates are made this should cause (almost?) no functional changes. Theoretically, this will prevent instructions like LDMXCSR and STMXCSR from being moved past one another, but that should be prevented anyway and I haven't found a case where it is happening now.
Differential Revision: https://reviews.llvm.org/D29903
llvm-svn: 295004
Summary: Small change to get the FREEP instruction to decode properly.
Reviewers: craig.topper
Reviewed By: craig.topper
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D29193
llvm-svn: 293314
The names of the tablegen defs now match the names of the ISD nodes.
This makes the world a slightly saner place, as previously "fround" matched
ISD::FP_ROUND and not ISD::FROUND.
Differential Revision: https://reviews.llvm.org/D23597
llvm-svn: 279129
|9B DD /7| FSTSW m2byte| Valid Valid Store FPU status word at m2byteafter checking for pending unmasked floating-point exceptions.|
|9B DF E0| FSTSW AX| Valid Valid Store FPU status word in AX register after checking for pending unmasked floating-point exceptions.|
|DD /7 |FNSTSW *m2byte| Valid Valid Store FPU status word at m2bytewithout checking for pending unmasked floating-point exceptions.|
|DF E0 |FNSTSW *AX| Valid Valid Store FPU status word in AX register without checking for pending unmasked floating-point exceptions|
m2byte is word register, and therefor instruction operand need to be change from f32mem to i16mem.
Differential Revision: http://reviews.llvm.org/D14953
llvm-svn: 254512
Not sure how to test this. I noticed by inspection in the isel tables where the same pattern tried to produce DIV and DIVR or SUB and SUBR.
llvm-svn: 254388
This was breaking sqlite with the machine verifier because operand 0 was a def according to tablegen, but didn't have the 'isDef' flag set.
Looking at the ISA, its clear that this operand is a source as writing to st(0) is implicit. So move the operand to the correct place in the td file.
rdar://problem/20751584
llvm-svn: 236183
Stop using ST registers for function returns and inline-asm instructions and use
FP registers instead. This allows removing a large amount of code in the
stackifier pass that was needed to track register liveness and handle copies
between ST and FP registers and function calls returning floating point values.
It also fixes a bug which manifests when an ST register defined by an
inline-asm instruction was live across another inline-asm instruction, as shown
in the following sequence of machine instructions:
1. INLINEASM <es:frndint> $0:[regdef], %ST0<imp-def,tied5>
2. INLINEASM <es:fldcw $0>
3. %FP0<def> = COPY %ST0
<rdar://problem/16952634>
llvm-svn: 214580
* Model FPSW (the FPU status word) as a register.
* Add ISel patterns for the FUCOM*, FNSTSW and SAHF instructions.
* During Legalize/Lowering, build a node sequence to transfer the comparison
result from FPSW into EFLAGS. If you're wondering about the right-shift: That's
an implicit sub-register extraction (%ax -> %ah) which is handled later on by
the instruction selector.
Fixes PR6679. Patch by Christoph Erhardt!
llvm-svn: 155704
Drop the FpMov instructions, use plain COPY instead.
Drop the FpSET/GET instruction for accessing fixed stack positions.
Instead use normal COPY to/from ST registers around inline assembly, and
provide a single new FpPOP_RETVAL instruction that can access the return
value(s) from a call. This is still necessary since you cannot tell from
the CALL instruction alone if it returns anything on the FP stack. Teach
fast isel to use this.
This provides a much more robust way of handling fixed stack registers -
we can tolerate arbitrary FP stack instructions inserted around calls
and inline assembly. Live range splitting could sometimes break x87 code
by inserting spill code in unfortunate places.
As a bonus we handle floating point inline assembly correctly now.
llvm-svn: 134018
These are just FXSAVE and FXRSTOR with REX.W prefixes. These versions use
64-bit pointer values instead of 32-bit pointer values in the memory map they
dump and restore.
llvm-svn: 125446
exposed:
GAS doesn't accept "fcomip %st(1)", it requires "fcomip %st(1), %st(0)"
even though st(0) is implicit in all other fp stack instructions.
Fortunately, there is an alias for fcomip named "fcompi" and gas does
accept the default argument for the alias (boggle!).
As such, switch the canonical form of this instruction to "pi" instead
of "ip". This makes the code generator and disassembler generate pi,
avoiding the gas bug.
llvm-svn: 118356
sense, when the instruction takes the 16-bit ax register or m16 memory
location. These changes to llvm-mc matches what the darwin assembler allows
for these instructions. Also added the missing flex (without the wait prefix)
and ud2a as an alias to ud2 (still to add ud2b).
llvm-svn: 117031
instructions as the Mac OS X darwin assembler. Some of which like 'fcoml'
assembled to different opcodes. While some of the suffixes were just different.
llvm-svn: 102958
to input patterns, we can fix X86ISD::CMP and X86ISD::BT as taking
two inputs (which have to be the same type) and *returning an i32*.
This is how the SDNodes get made in the graph, but we weren't able
to model it this way due to deficiencies in the pattern language.
Now we can change things like this:
def UCOM_FpIr80: FpI_<(outs), (ins RFP80:$lhs, RFP80:$rhs), CompareFP,
- [(X86cmp RFP80:$lhs, RFP80:$rhs),
- (implicit EFLAGS)]>; // CC = ST(0) cmp ST(i)
+ [(set EFLAGS, (X86cmp RFP80:$lhs, RFP80:$rhs))]>;
and fix terrible crimes like this:
-def : Pat<(parallel (X86cmp GR8:$src1, 0), (implicit EFLAGS)),
+def : Pat<(X86cmp GR8:$src1, 0),
(TEST8rr GR8:$src1, GR8:$src1)>;
This relies on matching the result of TEST8rr (which is EFLAGS, which is
an implicit def) to the result of X86cmp, an i32.
llvm-svn: 98903
Andrew Kaylor