[PATCH] D57044: [AArch64] Optimize Inf materialization

[Adhemerval Zanella via Phabricator via llvm-commits]

zatrazz created this revision.
zatrazz added reviewers: fhahn, javed.absar, huntergr, SjoerdMeijer, t.p.northover, echristo, evandro, rengolin.
Herald added a subscriber: kristof.beyls.

We can materialize Inf on isFPImmLegal for both float and double. It optimizes isinf slight as well.


Repository:
  rL LLVM

https://reviews.llvm.org/D57044

Files:
  lib/Target/AArch64/AArch64ISelLowering.cpp
  test/CodeGen/AArch64/known-never-nan.ll


Index: test/CodeGen/AArch64/known-never-nan.ll
===================================================================
--- test/CodeGen/AArch64/known-never-nan.ll
+++ test/CodeGen/AArch64/known-never-nan.ll
@@ -28,13 +28,13 @@
 define float @not_fmaxnm_maybe_nan(i32 %i1, i32 %i2) #0 {
 ; CHECK-LABEL: not_fmaxnm_maybe_nan:
 ; CHECK:       // %bb.0:
-; CHECK-NEXT:    adrp x8, .LCPI1_0
-; CHECK-NEXT:    ldr s0, [x8, :lo12:.LCPI1_0]
-; CHECK-NEXT:    ucvtf s1, w0
-; CHECK-NEXT:    ucvtf s2, w1
-; CHECK-NEXT:    fmov s3, #17.00000000
-; CHECK-NEXT:    fmul s0, s1, s0
-; CHECK-NEXT:    fadd s1, s2, s3
+; CHECK-NEXT:    orr w8, wzr, #0xff800000
+; CHECK-NEXT:    ucvtf s0, w0
+; CHECK-NEXT:    ucvtf s1, w1
+; CHECK-NEXT:    fmov s2, #17.00000000
+; CHECK-NEXT:    fmov s3, w8
+; CHECK-NEXT:    fmul s0, s0, s3
+; CHECK-NEXT:    fadd s1, s1, s2
 ; CHECK-NEXT:    fcmp s0, s1
 ; CHECK-NEXT:    fcsel s0, s0, s1, pl
 ; CHECK-NEXT:    ret
Index: lib/Target/AArch64/AArch64ISelLowering.cpp
===================================================================
--- lib/Target/AArch64/AArch64ISelLowering.cpp
+++ lib/Target/AArch64/AArch64ISelLowering.cpp
@@ -5426,11 +5426,14 @@
 }
 
 bool AArch64TargetLowering::isFPImmLegal(const APFloat &Imm, EVT VT) const {
-  // We can materialize #0.0 as fmov $Rd, XZR for 64-bit and 32-bit cases.
+  // We can materialize #0.0 and #INF as fmov $Rd, XZR for 64-bit and 32-bit
+  // cases.
   // FIXME: We should be able to handle f128 as well with a clever lowering.
-  if (Imm.isPosZero() && (VT == MVT::f64 || VT == MVT::f32 ||
-                          (VT == MVT::f16 && Subtarget->hasFullFP16()))) {
-    LLVM_DEBUG(dbgs() << "Legal " << VT.getEVTString() << " imm value: 0\n");
+  if ((Imm.isPosZero() || Imm.isInfinity()) &&
+      (VT == MVT::f64 || VT == MVT::f32 ||
+       (VT == MVT::f16 && Subtarget->hasFullFP16()))) {
+    LLVM_DEBUG(dbgs() << "Legal " << VT.getEVTString() << " imm value: "
+                      << (Imm.isPosZero() ? "0" : "Inf") << "\n");
     return true;
   }
 


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