Summary:
Even though there is no 2nd register operand in the "lw/sw $8, symbol" case, we still try to find one,
and we end up with $0, which makes us generate an unnecessary "addu $8, $8, $0" (a.k.a. "move $8, $8").
We can avoid this by checking if the 2nd register operand is different from $0, before generating the addu.
Reviewers: dsanders
Reviewed By: dsanders
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D8055
llvm-svn: 234406
Summary:
This pseudo-instruction allows the programmer to load an address from a symbolic expression into a register.
Patch by David Chisnall.
His work was sponsored by: DARPA, AFRL
I've made some minor changes to the original, such as improving the formatting and adding some comments, and I've also added a test case.
Reviewers: dsanders
Reviewed By: dsanders
Differential Revision: http://reviews.llvm.org/D4808
llvm-svn: 215630
Summary:
The assembler tries to reuse the destination register for memory operations whenever
it can but it's not possible to do so if the destination register is not a GPR.
Example:
ldc1 $f0, sym
should expand to:
lui $at, %hi(sym)
ldc1 $f0, %lo(sym)($at)
It's entirely wrong to expand to:
lui $f0, %hi(sym)
ldc1 $f0, %lo(sym)($f0)
Reviewers: dsanders
Reviewed By: dsanders
Differential Revision: http://reviews.llvm.org/D4173
llvm-svn: 211169
Summary:
This patch doesn't really change the logic behind expandMemInst but it allows
us to assemble .S files that use .set noat with some macros. For example:
.set noat
lw $k0, offset($k1)
Can expand to:
lui $k0, %hi(offset)
addu $k0, $k0, $k1
lw $k0, %lo(offset)($k0)
with no need to access $at.
Reviewers: dsanders, vmedic
Reviewed By: dsanders, vmedic
Differential Revision: http://reviews.llvm.org/D4159
llvm-svn: 211165
This patch uses the generated instruction info tables to
identify memory/load store instructions.
After successful matching and based on the operand type
and size, it generates additional instructions to the output.
Contributor: Vladimir Medic
llvm-svn: 177685
This patch provides initial implementation of load address
macro instruction for Mips. We have implemented two kinds
of expansions with their variations depending on the size
of immediate operand:
1) load address with immediate value directly:
* la d,j => addiu d,$zero,j (for -32768 <= j <= 65535)
* la d,j => lui d,hi16(j)
ori d,d,lo16(j) (for any other 32 bit value of j)
2) load load address with register offset value
* la d,j(s) => addiu d,s,j (for -32768 <= j <= 65535)
* la d,j(s) => lui d,hi16(j) (for any other 32 bit value of j)
ori d,d,lo16(j)
addu d,d,s
This patch does not cover the case when the address is loaded
from the value of the label or function.
Contributer: Vladimir Medic
llvm-svn: 165561
macro instruction (li) in the assembler.
We have identified three possible expansions depending on
the size of immediate operand:
1) for 0 ≤ j ≤ 65535.
li d,j =>
ori d,$zero,j
2) for −32768 ≤ j < 0.
li d,j =>
addiu d,$zero,j
3) for any other value of j that is representable as a 32-bit integer.
li d,j =>
lui d,hi16(j)
ori d,d,lo16(j)
All of the above have been implemented in ths patch.
Contributer: Vladimir Medic
llvm-svn: 165199
Toma Tabacu