[mips][mips64r6] c.cond.fmt, mov[fntz], and mov[fntz].[ds] are not available on MIPS32r6/MIPS64r6

Summary:
c.cond.fmt has been replaced by cmp.cond.fmt. Where c.cond.fmt wrote to
dedicated condition registers, cmp.cond.fmt writes 1 or 0 to normal FGR's
(like the GPR comparisons).

mov[fntz] have been replaced by seleqz and selnez. These instructions
conditionally zero a register based on a bool in a GPR. The results can
then be or'd together to act as a select without, for example, requiring a third
register read port.

mov[fntz].[ds] have been replaced with sel.[ds]

MIPS64r6 currently generates unnecessary sign-extensions for most selects.
This is because the result of a SETCC is currently an i32. Bits 32-63 are
undefined in i32 and the behaviour of seleqz/selnez would otherwise depend
on undefined bits. Later, we will fix this by making the result of SETCC an
i64 on MIPS64 targets.

Depends on D3958

Reviewers: jkolek, vmedic, zoran.jovanovic

Reviewed By: vmedic, zoran.jovanovic

Differential Revision: http://reviews.llvm.org/D4003

llvm-svn: 210777

1 files changed, 32 insertions, 0 deletions

diff --git a/llvm/lib/Target/Mips/MipsSEISelLowering.cpp b/llvm/lib/Target/Mips/MipsSEISelLowering.cpp
index 217059baf3b..2b196f873fe 100644
--- a/llvm/lib/Target/Mips/MipsSEISelLowering.cpp
+++ b/llvm/lib/Target/Mips/MipsSEISelLowering.cpp
@@ -169,6 +169,32 @@ MipsSETargetLowering::MipsSETargetLowering(MipsTargetMachine &TM)
     setOperationAction(ISD::UDIV, MVT::i32, Legal);
     setOperationAction(ISD::SREM, MVT::i32, Legal);
     setOperationAction(ISD::UREM, MVT::i32, Legal);
+
+    // MIPS32r6 replaces conditional moves with an equivalent that removes the
+    // need for three GPR read ports.
+    setOperationAction(ISD::SETCC, MVT::i32, Legal);
+    setOperationAction(ISD::SELECT, MVT::i32, Legal);
+    setOperationAction(ISD::SELECT_CC, MVT::i32, Expand);
+
+    setOperationAction(ISD::SETCC, MVT::f32, Legal);
+    setOperationAction(ISD::SELECT, MVT::f32, Legal);
+    setOperationAction(ISD::SELECT_CC, MVT::f32, Expand);
+
+    assert(Subtarget->isFP64bit() && "FR=1 is required for MIPS32r6");
+    setOperationAction(ISD::SETCC, MVT::f64, Legal);
+    setOperationAction(ISD::SELECT, MVT::f64, Legal);
+    setOperationAction(ISD::SELECT_CC, MVT::f64, Expand);
+
+    // Floating point > and >= are supported via < and <=
+    setCondCodeAction(ISD::SETOGE, MVT::f32, Expand);
+    setCondCodeAction(ISD::SETOGT, MVT::f32, Expand);
+    setCondCodeAction(ISD::SETUGE, MVT::f32, Expand);
+    setCondCodeAction(ISD::SETUGT, MVT::f32, Expand);
+
+    setCondCodeAction(ISD::SETOGE, MVT::f64, Expand);
+    setCondCodeAction(ISD::SETOGT, MVT::f64, Expand);
+    setCondCodeAction(ISD::SETUGE, MVT::f64, Expand);
+    setCondCodeAction(ISD::SETUGT, MVT::f64, Expand);
   }
 
   if (Subtarget->hasMips64r6()) {
@@ -186,6 +212,12 @@ MipsSETargetLowering::MipsSETargetLowering(MipsTargetMachine &TM)
     setOperationAction(ISD::UDIV, MVT::i64, Legal);
     setOperationAction(ISD::SREM, MVT::i64, Legal);
     setOperationAction(ISD::UREM, MVT::i64, Legal);
+
+    // MIPS64r6 replaces conditional moves with an equivalent that removes the
+    // need for three GPR read ports.
+    setOperationAction(ISD::SETCC, MVT::i64, Legal);
+    setOperationAction(ISD::SELECT, MVT::i64, Legal);
+    setOperationAction(ISD::SELECT_CC, MVT::i64, Expand);
   }
 
   computeRegisterProperties();