[PATCH] D50115: [AArch64] Fix FCCMP with FP16 operands

[Bryan Chan via Phabricator via llvm-commits]

bryanpkc created this revision.
bryanpkc added reviewers: olista01, SjoerdMeijer, t.p.northover.
Herald added a reviewer: javed.absar.
Herald added subscribers: llvm-commits, kristof.beyls.

This patch adds support for FCCMP instruction with FP16 operands, avoiding an assertion during instruction selection.


Repository:
  rL LLVM

https://reviews.llvm.org/D50115

Files:
  lib/Target/AArch64/AArch64InstrFormats.td
  test/CodeGen/AArch64/f16-instructions.ll


Index: test/CodeGen/AArch64/f16-instructions.ll
===================================================================
--- test/CodeGen/AArch64/f16-instructions.ll
+++ test/CodeGen/AArch64/f16-instructions.ll
@@ -456,6 +456,36 @@
   ret i1 %r
 }
 
+; CHECK-COMMON-LABEL: test_fccmp:
+; CHECK-CVT:      fcvt  s0, h0
+; CHECK-CVT-NEXT: fmov  s1, #8.00000000
+; CHECK-CVT-NEXT: fmov  s2, #5.00000000
+; CHECK-CVT-NEXT: fcmp  s0, s1
+; CHECK-CVT-NEXT: cset  w8, gt
+; CHECK-CVT-NEXT: fcmp  s0, s2
+; CHECK-CVT-NEXT: cset  w9, mi
+; CHECK-CVT-NEXT: tst   w8, w9
+; CHECK-CVT-NEXT: fcsel s0, s0, s2, ne
+; CHECK-CVT-NEXT: fcvt  h0, s0
+; CHECK-CVT-NEXT: str   h0, [x0]
+; CHECK-CVT-NEXT: ret
+; CHECK-FP16:      fmov  h1, #5.00000000
+; CHECK-FP16-NEXT: fcmp  h0, h1
+; CHECK-FP16-NEXT: fmov  h2, #8.00000000
+; CHECK-FP16-NEXT: fccmp h0, h2, #4, mi
+; CHECK-FP16-NEXT: fcsel h0, h0, h1, gt
+; CHECK-FP16-NEXT: str   h0, [x0]
+; CHECK-FP16-NEXT: ret
+
+define void @test_fccmp(half %in, half* %out) {
+  %cmp1 = fcmp ogt half %in, 0xH4800
+  %cmp2 = fcmp olt half %in, 0xH4500
+  %cond = and i1 %cmp1, %cmp2
+  %result = select i1 %cond, half %in, half 0xH4500
+  store half %result, half* %out
+  ret void
+}
+
 ; CHECK-CVT-LABEL: test_br_cc:
 ; CHECK-CVT-NEXT: fcvt s1, h1
 ; CHECK-CVT-NEXT: fcvt s0, h0
Index: lib/Target/AArch64/AArch64InstrFormats.td
===================================================================
--- lib/Target/AArch64/AArch64InstrFormats.td
+++ lib/Target/AArch64/AArch64InstrFormats.td
@@ -4639,7 +4639,9 @@
 
 multiclass FPCondComparison<bit signalAllNans, string mnemonic,
                             SDPatternOperator OpNode = null_frag> {
-  def Hrr : BaseFPCondComparison<signalAllNans, FPR16, mnemonic, []> {
+  def Hrr : BaseFPCondComparison<signalAllNans, FPR16, mnemonic,
+      [(set NZCV, (OpNode (f16 FPR16:$Rn), (f16 FPR16:$Rm), (i32 imm:$nzcv),
+                          (i32 imm:$cond), NZCV))]> {
     let Inst{23-22} = 0b11;
     let Predicates = [HasFullFP16];
   }


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