[RISCV][GISel] Legalize the G_FCANONICALIZE instruction (#166162)

Author: circYuan

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

@@ -639,6 +639,11 @@ RISCVLegalizerInfo::RISCVLegalizerInfo(const RISCVSubtarget &ST)
       .libcallFor({{s32, s32}, {s64, s32}})
       .libcallFor(ST.is64Bit(), {s128, s32});
 
+  getActionDefinitionsBuilder(G_FCANONICALIZE)
+      .legalFor(ST.hasStdExtF(), {s32})
+      .legalFor(ST.hasStdExtD(), {s64})
+      .legalFor(ST.hasStdExtZfh(), {s16});
+
   getActionDefinitionsBuilder(G_VASTART).customFor({p0});
 
   // va_list must be a pointer, but most sized types are pretty easy to handle

llvm/test/CodeGen/RISCV/GlobalISel/fp-fcanonicalize.ll

@@ -0,0 +1,66 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; FIXME: @llvm.canonicalize doesn't support soft-float abi yet.
+; RUN: llc -mtriple=riscv64 -mattr=+d,+zfh -global-isel < %s | FileCheck %s --check-prefixes=CHECK,CHECK-FP16-RV64
+; RUN: llc -mtriple=riscv32 -mattr=+d,+zfh -global-isel < %s | FileCheck %s --check-prefixes=CHECK,CHECK-FP16-RV32
+
+declare half @llvm.fcanonicalize.f16(half)
+declare float @llvm.fcanonicalize.f32(float)
+declare double @llvm.fcanonicalize.f64(double)
+
+define half @fcanonicalize_f16(half %x) {
+; CHECK-LABEL: fcanonicalize_f16:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    fmin.h fa0, fa0, fa0
+; CHECK-NEXT:    ret
+  %z = call half @llvm.canonicalize.f16(half %x)
+  ret half %z
+}
+
+define half @fcanonicalize_f16_nnan(half %x) {
+; CHECK-LABEL: fcanonicalize_f16_nnan:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    fmin.h fa0, fa0, fa0
+; CHECK-NEXT:    ret
+  %z = call nnan half @llvm.canonicalize.f16(half %x)
+  ret half %z
+}
+
+define float @fcanonicalize_f32(float %x) {
+; CHECK-LABEL: fcanonicalize_f32:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    fmin.s fa0, fa0, fa0
+; CHECK-NEXT:    ret
+  %z = call float @llvm.canonicalize.f32(float %x)
+  ret float %z
+}
+
+define float @fcanonicalize_f32_nnan(float %x) {
+; CHECK-LABEL: fcanonicalize_f32_nnan:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    fmin.s fa0, fa0, fa0
+; CHECK-NEXT:    ret
+  %z = call nnan float @llvm.canonicalize.f32(float %x)
+  ret float %z
+}
+
+define double @fcanonicalize_f64(double %x) {
+; CHECK-LABEL: fcanonicalize_f64:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    fmin.d fa0, fa0, fa0
+; CHECK-NEXT:    ret
+  %z = call double @llvm.canonicalize.f64(double %x)
+  ret double %z
+}
+
+define double @fcanonicalize_f64_nnan(double %x) {
+; CHECK-LABEL: fcanonicalize_f64_nnan:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    fmin.d fa0, fa0, fa0
+; CHECK-NEXT:    ret
+  %z = call nnan double @llvm.canonicalize.f64(double %x)
+  ret double %z
+}
+
+;; NOTE: These prefixes are unused and the list is autogenerated. Do not add tests below this line:
+; CHECK-FP16-RV32: {{.*}}
+; CHECK-FP16-RV64: {{.*}}

llvm/test/CodeGen/RISCV/GlobalISel/legalizer-info-validation.mir

@@ -603,8 +603,8 @@
 # DEBUG-NEXT: .. the first uncovered type index: 2, OK
 # DEBUG-NEXT: .. the first uncovered imm index: 0, OK
 # DEBUG-NEXT: G_FCANONICALIZE (opcode {{[0-9]+}}): 1 type index, 0 imm indices
-# DEBUG-NEXT: .. type index coverage check SKIPPED: no rules defined
-# DEBUG-NEXT: .. imm index coverage check SKIPPED: no rules defined
+# DEBUG-NEXT: .. the first uncovered type index: 1, OK
+# DEBUG-NEXT: .. the first uncovered imm index: 0, OK
 # DEBUG-NEXT: G_FMINNUM (opcode {{[0-9]+}}): 1 type index
 # DEBUG-NEXT: .. opcode {{[0-9]+}} is aliased to {{[0-9]+}}
 # DEBUG-NEXT: .. the first uncovered type index: 1, OK