Improved the operands commute transformation for X86-FMA3 instructions.
All 3 operands of FMA3 instructions are commutable now.
Patch by Slava Klochkov
Reviewers: Quentin Colombet(qcolombet), Ahmed Bougacha(ab).
Differential Revision: http://reviews.llvm.org/D13269
llvm-svn: 252335
diff --git a/llvm/lib/Target/X86/X86InstrInfo.h b/llvm/lib/Target/X86/X86InstrInfo.h
index 3f6b030..edd09d6 100644
--- a/llvm/lib/Target/X86/X86InstrInfo.h
+++ b/llvm/lib/Target/X86/X86InstrInfo.h
@@ -264,6 +264,46 @@
bool findCommutedOpIndices(MachineInstr *MI, unsigned &SrcOpIdx1,
unsigned &SrcOpIdx2) const override;
+ /// Returns true if the routine could find two commutable operands
+ /// in the given FMA instruction. Otherwise, returns false.
+ ///
+ /// \p SrcOpIdx1 and \p SrcOpIdx2 are INPUT and OUTPUT arguments.
+ /// The output indices of the commuted operands are returned in these
+ /// arguments. Also, the input values of these arguments may be preset either
+ /// to indices of operands that must be commuted or be equal to a special
+ /// value 'CommuteAnyOperandIndex' which means that the corresponding
+ /// operand index is not set and this method is free to pick any of
+ /// available commutable operands.
+ ///
+ /// For example, calling this method this way:
+ /// unsigned Idx1 = 1, Idx2 = CommuteAnyOperandIndex;
+ /// findFMA3CommutedOpIndices(MI, Idx1, Idx2);
+ /// can be interpreted as a query asking if the operand #1 can be swapped
+ /// with any other available operand (e.g. operand #2, operand #3, etc.).
+ ///
+ /// The returned FMA opcode may differ from the opcode in the given MI.
+ /// For example, commuting the operands #1 and #3 in the following FMA
+ /// FMA213 #1, #2, #3
+ /// results into instruction with adjusted opcode:
+ /// FMA231 #3, #2, #1
+ bool findFMA3CommutedOpIndices(MachineInstr *MI,
+ unsigned &SrcOpIdx1,
+ unsigned &SrcOpIdx2) const;
+
+ /// Returns an adjusted FMA opcode that must be used in FMA instruction that
+ /// performs the same computations as the given MI but which has the operands
+ /// \p SrcOpIdx1 and \p SrcOpIdx2 commuted.
+ /// It may return 0 if it is unsafe to commute the operands.
+ ///
+ /// The returned FMA opcode may differ from the opcode in the given \p MI.
+ /// For example, commuting the operands #1 and #3 in the following FMA
+ /// FMA213 #1, #2, #3
+ /// results into instruction with adjusted opcode:
+ /// FMA231 #3, #2, #1
+ unsigned getFMA3OpcodeToCommuteOperands(MachineInstr *MI,
+ unsigned SrcOpIdx1,
+ unsigned SrcOpIdx2) const;
+
// Branch analysis.
bool isUnpredicatedTerminator(const MachineInstr* MI) const override;
bool AnalyzeBranch(MachineBasicBlock &MBB, MachineBasicBlock *&TBB,