AArch64: Select FCANONICALIZE

[wzssyqa]

FMINNM/FMAXNM instructions of AArch64 follow IEEE754-2008. We can use them to canonicalize a floating point number. And FMINNUM_IEEE/FMAXNUM_IEEE is used by something like expanding FMINIMUMNUM/FMAXIMUMNUM, so let's define them.

[llvmbot]

@llvm/pr-subscribers-backend-aarch64

Author: YunQiang Su (wzssyqa)

Changes

FMINNM/FMAXNM instructions of AArch64 follow IEEE754-2008. We can use them to canonicalize a floating point number. And FMINNUM_IEEE/FMAXNUM_IEEE is used by something like expanding FMINIMUMNUM/FMAXIMUMNUM, so let's define them.

---

Full diff: https://github.com/llvm/llvm-project/pull/104429.diff

2 Files Affected:

• (modified) llvm/lib/Target/AArch64/AArch64ISelLowering.cpp (+32-11)
• (modified) llvm/lib/Target/AArch64/AArch64InstrInfo.td (+12)

diff --git a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
index 97fb2c5f552731..b34d1eaf8828e2 100644
--- a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
+++ b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
@@ -860,17 +860,38 @@ AArch64TargetLowering::AArch64TargetLowering(const TargetMachine &TM,
   setOperationAction(ISD::FP_ROUND, MVT::v4bf16, Custom);
 
   // AArch64 has implementations of a lot of rounding-like FP operations.
-  for (auto Op :
-       {ISD::FFLOOR,          ISD::FNEARBYINT,      ISD::FCEIL,
-        ISD::FRINT,           ISD::FTRUNC,          ISD::FROUND,
-        ISD::FROUNDEVEN,      ISD::FMINNUM,         ISD::FMAXNUM,
-        ISD::FMINIMUM,        ISD::FMAXIMUM,        ISD::LROUND,
-        ISD::LLROUND,         ISD::LRINT,           ISD::LLRINT,
-        ISD::STRICT_FFLOOR,   ISD::STRICT_FCEIL,    ISD::STRICT_FNEARBYINT,
-        ISD::STRICT_FRINT,    ISD::STRICT_FTRUNC,   ISD::STRICT_FROUNDEVEN,
-        ISD::STRICT_FROUND,   ISD::STRICT_FMINNUM,  ISD::STRICT_FMAXNUM,
-        ISD::STRICT_FMINIMUM, ISD::STRICT_FMAXIMUM, ISD::STRICT_LROUND,
-        ISD::STRICT_LLROUND,  ISD::STRICT_LRINT,    ISD::STRICT_LLRINT}) {
+  for (auto Op : {ISD::FFLOOR,
+                  ISD::FNEARBYINT,
+                  ISD::FCEIL,
+                  ISD::FRINT,
+                  ISD::FTRUNC,
+                  ISD::FROUND,
+                  ISD::FROUNDEVEN,
+                  ISD::FMINNUM,
+                  ISD::FMAXNUM,
+                  ISD::FMINNUM_IEEE,
+                  ISD::FMAXNUM_IEEE,
+                  ISD::FMINIMUM,
+                  ISD::FMAXIMUM,
+                  ISD::LROUND,
+                  ISD::LLROUND,
+                  ISD::LRINT,
+                  ISD::LLRINT,
+                  ISD::STRICT_FFLOOR,
+                  ISD::STRICT_FCEIL,
+                  ISD::STRICT_FNEARBYINT,
+                  ISD::STRICT_FRINT,
+                  ISD::STRICT_FTRUNC,
+                  ISD::STRICT_FROUNDEVEN,
+                  ISD::STRICT_FROUND,
+                  ISD::STRICT_FMINNUM,
+                  ISD::STRICT_FMAXNUM,
+                  ISD::STRICT_FMINIMUM,
+                  ISD::STRICT_FMAXIMUM,
+                  ISD::STRICT_LROUND,
+                  ISD::STRICT_LLROUND,
+                  ISD::STRICT_LRINT,
+                  ISD::STRICT_LLRINT}) {
     for (MVT Ty : {MVT::f32, MVT::f64})
       setOperationAction(Op, Ty, Legal);
     if (Subtarget->hasFullFP16())
diff --git a/llvm/lib/Target/AArch64/AArch64InstrInfo.td b/llvm/lib/Target/AArch64/AArch64InstrInfo.td
index 403453a4ee0a92..fe69e5bd638b50 100644
--- a/llvm/lib/Target/AArch64/AArch64InstrInfo.td
+++ b/llvm/lib/Target/AArch64/AArch64InstrInfo.td
@@ -5051,6 +5051,18 @@ def : Pat<(v1f64 (fmaxnum (v1f64 FPR64:$Rn), (v1f64 FPR64:$Rm))),
 def : Pat<(v1f64 (fminnum (v1f64 FPR64:$Rn), (v1f64 FPR64:$Rm))),
           (FMINNMDrr FPR64:$Rn, FPR64:$Rm)>;
 
+def : Pat<(fminnum_ieee (f64 FPR64:$a), (f64 FPR64:$b)),
+          (FMINNMDrr FPR64:$a, FPR64:$b)>;
+def : Pat<(fminnum_ieee (f32 FPR32:$a), (f32 FPR32:$b)),
+          (FMINNMSrr FPR32:$a, FPR32:$b)>;
+def : Pat<(fmaxnum_ieee (f64 FPR64:$a), (f64 FPR64:$b)),
+          (FMAXNMDrr FPR64:$a, FPR64:$b)>;
+def : Pat<(fmaxnum_ieee (f32 FPR32:$a), (f32 FPR32:$b)),
+          (FMAXNMSrr FPR32:$a, FPR32:$b)>;
+def : Pat<(f32 (fcanonicalize f32:$a)),
+          (FMINSrr   f32:$a, f32:$a)>;
+def : Pat<(f64 (fcanonicalize f64:$a)),
+          (FMINDrr   f64:$a, f64:$a)>;
 //===----------------------------------------------------------------------===//
 // Floating point three operand instructions.
 //===----------------------------------------------------------------------===//

[wzssyqa]

ping

[arsenm]

In future could try to select to a copy in cases where the source is known canonicalized already

[github-actions]

✅ With the latest revision this PR passed the C/C++ code formatter.

[davemgreen]

Thanks for doing this. LGTM with some suggestions for where code can be moved.