[RISCV][GISel] Enable libcall expansion for G_FCEIL and G_FFLOOR.

Author: topperc

llvm/lib/Target/RISCV/GISel/RISCVLegalizerInfo.cpp

@@ -237,6 +237,11 @@ RISCVLegalizerInfo::RISCVLegalizerInfo(const RISCVSubtarget &ST) {
       .widenScalarToNextPow2(1)
       .clampScalar(1, s32, sXLen);
 
+  // FIXME: We can do custom inline expansion like SelectionDAG.
+  // FIXME: Legal with Zfa.
+  getActionDefinitionsBuilder({G_FCEIL, G_FFLOOR})
+      .libcallFor({s32, s64});
+
   getLegacyLegalizerInfo().computeTables();
 }
 

llvm/test/CodeGen/RISCV/GlobalISel/legalizer/legalize-fp-ceil-floor.mir

@@ -0,0 +1,98 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
+# RUN: llc -mtriple=riscv32 -mattr=+d -run-pass=legalizer %s -o - \
+# RUN: | FileCheck %s
+# RUN: llc -mtriple=riscv64 -mattr=+d -run-pass=legalizer %s -o - \
+# RUN: | FileCheck %s
+
+---
+name:            ceil_f32
+body:             |
+  bb.1:
+    liveins: $f10_f
+
+    ; CHECK-LABEL: name: ceil_f32
+    ; CHECK: liveins: $f10_f
+    ; CHECK-NEXT: {{  $}}
+    ; CHECK-NEXT: [[COPY:%[0-9]+]]:_(s32) = COPY $f10_f
+    ; CHECK-NEXT: ADJCALLSTACKDOWN 0, 0, implicit-def $x2, implicit $x2
+    ; CHECK-NEXT: $f10_f = COPY [[COPY]](s32)
+    ; CHECK-NEXT: PseudoCALL target-flags(riscv-call) &ceilf, csr_ilp32d_lp64d, implicit-def $x1, implicit $f10_f, implicit-def $f10_f
+    ; CHECK-NEXT: ADJCALLSTACKUP 0, 0, implicit-def $x2, implicit $x2
+    ; CHECK-NEXT: [[COPY1:%[0-9]+]]:_(s32) = COPY $f10_f
+    ; CHECK-NEXT: $f10_f = COPY [[COPY1]](s32)
+    ; CHECK-NEXT: PseudoRET implicit $f10_f
+    %0:_(s32) = COPY $f10_f
+    %1:_(s32) = G_FCEIL %0
+    $f10_f = COPY %1(s32)
+    PseudoRET implicit $f10_f
+
+...
+---
+name:            floor_f32
+body:             |
+  bb.1:
+    liveins: $f10_f
+
+    ; CHECK-LABEL: name: floor_f32
+    ; CHECK: liveins: $f10_f
+    ; CHECK-NEXT: {{  $}}
+    ; CHECK-NEXT: [[COPY:%[0-9]+]]:_(s32) = COPY $f10_f
+    ; CHECK-NEXT: ADJCALLSTACKDOWN 0, 0, implicit-def $x2, implicit $x2
+    ; CHECK-NEXT: $f10_f = COPY [[COPY]](s32)
+    ; CHECK-NEXT: PseudoCALL target-flags(riscv-call) &floorf, csr_ilp32d_lp64d, implicit-def $x1, implicit $f10_f, implicit-def $f10_f
+    ; CHECK-NEXT: ADJCALLSTACKUP 0, 0, implicit-def $x2, implicit $x2
+    ; CHECK-NEXT: [[COPY1:%[0-9]+]]:_(s32) = COPY $f10_f
+    ; CHECK-NEXT: $f10_f = COPY [[COPY1]](s32)
+    ; CHECK-NEXT: PseudoRET implicit $f10_f
+    %0:_(s32) = COPY $f10_f
+    %1:_(s32) = G_FFLOOR %0
+    $f10_f = COPY %1(s32)
+    PseudoRET implicit $f10_f
+
+...
+---
+name:            ceil_f64
+body:             |
+  bb.1:
+    liveins: $f10_d
+
+    ; CHECK-LABEL: name: ceil_f64
+    ; CHECK: liveins: $f10_d
+    ; CHECK-NEXT: {{  $}}
+    ; CHECK-NEXT: [[COPY:%[0-9]+]]:_(s64) = COPY $f10_d
+    ; CHECK-NEXT: ADJCALLSTACKDOWN 0, 0, implicit-def $x2, implicit $x2
+    ; CHECK-NEXT: $f10_d = COPY [[COPY]](s64)
+    ; CHECK-NEXT: PseudoCALL target-flags(riscv-call) &ceil, csr_ilp32d_lp64d, implicit-def $x1, implicit $f10_d, implicit-def $f10_d
+    ; CHECK-NEXT: ADJCALLSTACKUP 0, 0, implicit-def $x2, implicit $x2
+    ; CHECK-NEXT: [[COPY1:%[0-9]+]]:_(s64) = COPY $f10_d
+    ; CHECK-NEXT: $f10_d = COPY [[COPY1]](s64)
+    ; CHECK-NEXT: PseudoRET implicit $f10_d
+    %0:_(s64) = COPY $f10_d
+    %1:_(s64) = G_FCEIL %0
+    $f10_d = COPY %1(s64)
+    PseudoRET implicit $f10_d
+
+...
+---
+name:            floor_f64
+body:             |
+  bb.1:
+    liveins: $f10_d
+
+    ; CHECK-LABEL: name: floor_f64
+    ; CHECK: liveins: $f10_d
+    ; CHECK-NEXT: {{  $}}
+    ; CHECK-NEXT: [[COPY:%[0-9]+]]:_(s64) = COPY $f10_d
+    ; CHECK-NEXT: ADJCALLSTACKDOWN 0, 0, implicit-def $x2, implicit $x2
+    ; CHECK-NEXT: $f10_d = COPY [[COPY]](s64)
+    ; CHECK-NEXT: PseudoCALL target-flags(riscv-call) &floor, csr_ilp32d_lp64d, implicit-def $x1, implicit $f10_d, implicit-def $f10_d
+    ; CHECK-NEXT: ADJCALLSTACKUP 0, 0, implicit-def $x2, implicit $x2
+    ; CHECK-NEXT: [[COPY1:%[0-9]+]]:_(s64) = COPY $f10_d
+    ; CHECK-NEXT: $f10_d = COPY [[COPY1]](s64)
+    ; CHECK-NEXT: PseudoRET implicit $f10_d
+    %0:_(s64) = COPY $f10_d
+    %1:_(s64) = G_FFLOOR %0
+    $f10_d = COPY %1(s64)
+    PseudoRET implicit $f10_d
+
+...