[Flang] Generate math.erfc op for non-precise erfc interinsic calls (#128897)

This patch changes the codegen for non-precise erfc calls to generate
math.erfc ops. This wasn't done before because the math dialect did not
have a erfc operation at the time.

Author: jsjodin

flang/lib/Optimizer/Builder/IntrinsicCall.cpp

@@ -1277,8 +1277,10 @@ static constexpr MathOperation mathOperations[] = {
     {"erf", "erf", genFuncType<Ty::Real<8>, Ty::Real<8>>,
      genMathOp<mlir::math::ErfOp>},
     {"erf", RTNAME_STRING(ErfF128), FuncTypeReal16Real16, genLibF128Call},
-    {"erfc", "erfcf", genFuncType<Ty::Real<4>, Ty::Real<4>>, genLibCall},
-    {"erfc", "erfc", genFuncType<Ty::Real<8>, Ty::Real<8>>, genLibCall},
+    {"erfc", "erfcf", genFuncType<Ty::Real<4>, Ty::Real<4>>,
+     genMathOp<mlir::math::ErfcOp>},
+    {"erfc", "erfc", genFuncType<Ty::Real<8>, Ty::Real<8>>,
+     genMathOp<mlir::math::ErfcOp>},
     {"erfc", RTNAME_STRING(ErfcF128), FuncTypeReal16Real16, genLibF128Call},
     {"exp", "expf", genFuncType<Ty::Real<4>, Ty::Real<4>>,
      genMathOp<mlir::math::ExpOp>},

flang/test/Lower/Intrinsics/erfc.f90

@@ -1,22 +1,26 @@
-! RUN: bbc -emit-fir %s -o - --math-runtime=fast | FileCheck --check-prefixes=ALL %s
-! RUN: %flang_fc1 -emit-fir -mllvm -math-runtime=fast %s -o - | FileCheck --check-prefixes=ALL %s
-! RUN: bbc -emit-fir %s -o - --math-runtime=relaxed | FileCheck --check-prefixes=ALL %s
-! RUN: %flang_fc1 -emit-fir -mllvm -math-runtime=relaxed %s -o - | FileCheck --check-prefixes=ALL %s
-! RUN: bbc -emit-fir %s -o - --math-runtime=precise | FileCheck --check-prefixes=ALL %s
-! RUN: %flang_fc1 -emit-fir -mllvm -math-runtime=precise %s -o - | FileCheck --check-prefixes=ALL %s
+! RUN: bbc -emit-fir %s -o - --math-runtime=fast | FileCheck --check-prefixes=ALL,FAST %s
+! RUN: %flang_fc1 -emit-fir -mllvm -math-runtime=fast %s -o - | FileCheck --check-prefixes=ALL,FAST %s
+! RUN: bbc -emit-fir %s -o - --math-runtime=relaxed | FileCheck --check-prefixes=ALL,RELAXED %s
+! RUN: %flang_fc1 -emit-fir -mllvm -math-runtime=relaxed %s -o - | FileCheck --check-prefixes=ALL,RELAXED %s
+! RUN: bbc -emit-fir %s -o - --math-runtime=precise | FileCheck --check-prefixes=ALL,PRECISE %s
+! RUN: %flang_fc1 -emit-fir -mllvm -math-runtime=precise %s -o - | FileCheck --check-prefixes=ALL,PRECISE %s
 
 function test_real4(x)
   real :: x, test_real4
   test_real4 = erfc(x)
 end function
 
 ! ALL-LABEL: @_QPtest_real4
-! ALL: {{%[A-Za-z0-9._]+}} = fir.call @erfcf({{%[A-Za-z0-9._]+}}) {{.*}}: (f32) -> f32
+! FAST: {{%[A-Za-z0-9._]+}} = math.erfc {{%[A-Za-z0-9._]+}} {{.*}}: f32
+! RELAXED: {{%[A-Za-z0-9._]+}} = math.erfc {{%[A-Za-z0-9._]+}} {{.*}}: f32
+! PRECISE: {{%[A-Za-z0-9._]+}} = fir.call @erfcf({{%[A-Za-z0-9._]+}}) {{.*}}: (f32) -> f32
 
 function test_real8(x)
   real(8) :: x, test_real8
   test_real8 = erfc(x)
 end function
 
 ! ALL-LABEL: @_QPtest_real8
-! ALL: {{%[A-Za-z0-9._]+}} = fir.call @erfc({{%[A-Za-z0-9._]+}}) {{.*}}: (f64) -> f64
+! FAST: {{%[A-Za-z0-9._]+}} = math.erfc {{%[A-Za-z0-9._]+}} {{.*}}: f64
+! RELAXED: {{%[A-Za-z0-9._]+}} = math.erfc {{%[A-Za-z0-9._]+}} {{.*}}: f64
+! PRECISE: {{%[A-Za-z0-9._]+}} = fir.call @erfc({{%[A-Za-z0-9._]+}}) {{.*}}: (f64) -> f64