[flang] Fix complex libm use logic problems

Fix the various complex libm selection logic issues from D155310:
- disableMlirComplex is set to false. This means that using mlir complex
is enabled. Yet, the current code still selects libm.
- If we enable mlir complex, we should not check if use approx is
enabled. Namely, we should use mlir complex either if we enable mlir
complex OR use approx is enabled.

To fix the issues, we flip the logic of `disableMlirComplex` to enable
instead. We set it to false by default since the intention from D155310
is to use libm by default. Then we use a logical `&&` with use approx
so that we select libm when BOTH mlir complex and use approx are
disabled.

Reviewed By: vzakhari

Differential Revision: https://reviews.llvm.org/D155737

6 files changed, 36 insertions, 25 deletions

diff --git a/flang/lib/Optimizer/Builder/IntrinsicCall.cpp b/flang/lib/Optimizer/Builder/IntrinsicCall.cpp
index cb6bc26..3d2ae08 100644
--- a/flang/lib/Optimizer/Builder/IntrinsicCall.cpp
+++ b/flang/lib/Optimizer/Builder/IntrinsicCall.cpp
@@ -572,10 +572,10 @@ llvm::cl::opt<MathRuntimeVersion> mathRuntimeVersion(
     llvm::cl::init(fastVersion));
 
 static llvm::cl::opt<bool>
-    disableMlirComplex("disable-mlir-complex",
-                       llvm::cl::desc("Use libm instead of the MLIR complex "
-                                      "dialect to lower complex operations"),
-                       llvm::cl::init(false));
+    forceMlirComplex("force-mlir-complex",
+                     llvm::cl::desc("Force using MLIR complex operations "
+                                    "instead of libm complex operations"),
+                     llvm::cl::init(false));
 
 mlir::Value genLibCall(fir::FirOpBuilder &builder, mlir::Location loc,
                        llvm::StringRef libFuncName,
@@ -734,12 +734,19 @@ mlir::Value genComplexMathOp(fir::FirOpBuilder &builder, mlir::Location loc,
                              mlir::FunctionType mathLibFuncType,
                              llvm::ArrayRef<mlir::Value> args) {
   mlir::Value result;
-  bool hasApproxFunc = mlir::arith::bitEnumContainsAny(
+  bool canUseApprox = mlir::arith::bitEnumContainsAny(
       builder.getFastMathFlags(), mlir::arith::FastMathFlags::afn);
-  if ((disableMlirComplex || !hasApproxFunc) && !mathLibFuncName.empty()) {
-    result = genLibCall(builder, loc, mathLibFuncName, mathLibFuncType, args);
-    LLVM_DEBUG(result.dump(); llvm::dbgs() << "\n");
-    return result;
+
+  // If we have libm functions, we can attempt to generate the more precise
+  // version of the complex math operation.
+  if (!mathLibFuncName.empty()) {
+    // If we enabled MLIR complex or can use approximate operations, we should
+    // NOT use libm.
+    if (!forceMlirComplex && !canUseApprox) {
+      result = genLibCall(builder, loc, mathLibFuncName, mathLibFuncType, args);
+      LLVM_DEBUG(result.dump(); llvm::dbgs() << "\n");
+      return result;
+    }
   }
 
   LLVM_DEBUG(llvm::dbgs() << "Generating '" << mathLibFuncName
diff --git a/flang/test/Lower/Intrinsics/abs.f90 b/flang/test/Lower/Intrinsics/abs.f90
index 896a146..d2288a1 100644
--- a/flang/test/Lower/Intrinsics/abs.f90
+++ b/flang/test/Lower/Intrinsics/abs.f90
@@ -1,9 +1,9 @@
 ! RUN: bbc -emit-fir %s -o - | FileCheck %s --check-prefixes="CHECK,CMPLX,CMPLX-PRECISE"
 ! RUN: bbc -emit-fir --math-runtime=precise %s -o - | FileCheck %s --check-prefixes="CMPLX,CMPLX-PRECISE"
-! RUN: bbc --disable-mlir-complex -emit-fir %s -o - | FileCheck %s --check-prefixes="CMPLX,CMPLX-PRECISE"
+! RUN: bbc --force-mlir-complex -emit-fir %s -o - | FileCheck %s --check-prefixes="CMPLX,CMPLX-FAST"
 ! RUN: %flang_fc1 -emit-fir %s -o - | FileCheck %s --check-prefixes="CHECK,CMPLX,CMPLX-PRECISE"
 ! RUN: %flang_fc1 -emit-fir -mllvm --math-runtime=precise %s -o - | FileCheck %s --check-prefixes="CMPLX,CMPLX-PRECISE"
-! RUN: %flang_fc1 -emit-fir -mllvm --disable-mlir-complex %s -o - | FileCheck %s --check-prefixes="CMPLX,CMPLX-PRECISE"
+! RUN: %flang_fc1 -emit-fir -mllvm --force-mlir-complex %s -o - | FileCheck %s --check-prefixes="CMPLX,CMPLX-FAST"
 ! RUN: %flang_fc1 -fapprox-func -emit-fir %s -o - | FileCheck %s --check-prefixes="CMPLX,CMPLX-FAST"
 
 ! Test abs intrinsic for various types (int, float, complex)
diff --git a/flang/test/Lower/Intrinsics/exp.f90 b/flang/test/Lower/Intrinsics/exp.f90
index 8188ba3..f128e54 100644
--- a/flang/test/Lower/Intrinsics/exp.f90
+++ b/flang/test/Lower/Intrinsics/exp.f90
@@ -1,10 +1,10 @@
 ! RUN: bbc -emit-fir -outline-intrinsics %s -o - | FileCheck %s --check-prefixes="CHECK,CMPLX,CMPLX-PRECISE"
 ! RUN: bbc -emit-fir --math-runtime=precise -outline-intrinsics %s -o - | FileCheck %s --check-prefixes="CMPLX,CMPLX-PRECISE"
-! RUN: bbc -emit-fir --disable-mlir-complex -outline-intrinsics %s -o - | FileCheck %s --check-prefixes="CMPLX,CMPLX-PRECISE"
+! RUN: bbc -emit-fir --force-mlir-complex -outline-intrinsics %s -o - | FileCheck %s --check-prefixes="CMPLX,CMPLX-FAST,CMPLX-MLIR"
 ! RUN: %flang_fc1 -emit-fir -mllvm -outline-intrinsics %s -o - | FileCheck %s --check-prefixes="CHECK,CMPLX,CMPLX-PRECISE"
-! RUN: %flang_fc1 -fapprox-func -emit-fir -mllvm -outline-intrinsics %s -o - | FileCheck %s --check-prefixes="CMPLX,CMPLX-FAST"
+! RUN: %flang_fc1 -fapprox-func -emit-fir -mllvm -outline-intrinsics %s -o - | FileCheck %s --check-prefixes="CMPLX,CMPLX-FAST,CMPLX-APPROX"
 ! RUN: %flang_fc1 -emit-fir -mllvm -outline-intrinsics -mllvm --math-runtime=precise %s -o - | FileCheck %s --check-prefixes="CMPLX,CMPLX-PRECISE"
-! RUN: %flang_fc1 -emit-fir -mllvm -outline-intrinsics -mllvm --disable-mlir-complex %s -o - | FileCheck %s --check-prefixes="CMPLX,CMPLX-PRECISE"
+! RUN: %flang_fc1 -emit-fir -mllvm -outline-intrinsics -mllvm --force-mlir-complex %s -o - | FileCheck %s --check-prefixes="CMPLX,CMPLX-FAST,CMPLX-MLIR"
 
 ! CHECK-LABEL: exp_testr
 ! CHECK-SAME: (%[[AREF:.*]]: !fir.ref<f32> {{.*}}, %[[BREF:.*]]: !fir.ref<f32> {{.*}})
@@ -56,8 +56,9 @@ end subroutine
 ! CHECK: %[[RESULT64_OUTLINE:.*]] = math.exp %[[ARG64_OUTLINE]] fastmath<contract> : f64
 ! CHECK: return %[[RESULT64_OUTLINE]] : f64
 
-! CMPLX-FAST-LABEL: private @fir.exp.contract_afn.z4.z4
+! CMPLX-APPROX-LABEL: private @fir.exp.contract_afn.z4.z4
 ! CMPLX-PRECISE-LABEL: private @fir.exp.contract.z4.z4
+! CMPLX-MLIR-LABEL: private @fir.exp.contract.z4.z4
 ! CMPLX-SAME: (%[[ARG32_OUTLINE:.*]]: !fir.complex<4>) -> !fir.complex<4>
 ! CMPLX-FAST: %[[C:.*]] = fir.convert %[[ARG32_OUTLINE]] : (!fir.complex<4>) -> complex<f32>
 ! CMPLX-FAST: %[[E:.*]] = complex.exp %[[C]] : complex<f32>
@@ -65,8 +66,9 @@ end subroutine
 ! CMPLX-PRECISE: %[[RESULT32_OUTLINE:.*]] = fir.call @cexpf(%[[ARG32_OUTLINE]]) fastmath<contract> : (!fir.complex<4>) -> !fir.complex<4>
 ! CMPLX: return %[[RESULT32_OUTLINE]] : !fir.complex<4>
 
-! CMPLX-FAST-LABEL: private @fir.exp.contract_afn.z8.z8
+! CMPLX-APPROX-LABEL: private @fir.exp.contract_afn.z8.z8
 ! CMPLX-PRECISE-LABEL: private @fir.exp.contract.z8.z8
+! CMPLX-MLIR-LABEL: private @fir.exp.contract.z8.z8
 ! CMPLX-SAME: (%[[ARG64_OUTLINE:.*]]: !fir.complex<8>) -> !fir.complex<8>
 ! CMPLX-FAST: %[[C:.*]] = fir.convert %[[ARG64_OUTLINE]] : (!fir.complex<8>) -> complex<f64>
 ! CMPLX-FAST: %[[E:.*]] = complex.exp %[[C]] : complex<f64>
diff --git a/flang/test/Lower/Intrinsics/log.f90 b/flang/test/Lower/Intrinsics/log.f90
index e39972d..49be4d9 100644
--- a/flang/test/Lower/Intrinsics/log.f90
+++ b/flang/test/Lower/Intrinsics/log.f90
@@ -1,10 +1,10 @@
 ! RUN: bbc -emit-fir -outline-intrinsics %s -o - | FileCheck %s --check-prefixes="CHECK,CMPLX,CMPLX-PRECISE"
 ! RUN: bbc -emit-fir --math-runtime=precise -outline-intrinsics %s -o - | FileCheck %s --check-prefixes="CMPLX,CMPLX-PRECISE"
-! RUN: bbc -emit-fir --disable-mlir-complex -outline-intrinsics %s -o - | FileCheck %s --check-prefixes="CMPLX,CMPLX-PRECISE"
+! RUN: bbc -emit-fir --force-mlir-complex -outline-intrinsics %s -o - | FileCheck %s --check-prefixes="CMPLX,CMPLX-FAST,CMPLX-MLIR"
 ! RUN: %flang_fc1 -emit-fir -mllvm -outline-intrinsics %s -o - | FileCheck %s --check-prefixes="CHECK,CMPLX,CMPLX-PRECISE"
 ! RUN: %flang_fc1 -emit-fir -mllvm -outline-intrinsics -mllvm --math-runtime=precise %s -o - | FileCheck %s --check-prefixes="CMPLX,CMPLX-PRECISE"
-! RUN: %flang_fc1 -emit-fir -mllvm -outline-intrinsics -mllvm --disable-mlir-complex %s -o - | FileCheck %s --check-prefixes="CMPLX,CMPLX-PRECISE"
-! RUN: %flang_fc1 -fapprox-func -emit-fir -mllvm -outline-intrinsics %s -o - | FileCheck %s --check-prefixes="CMPLX,CMPLX-FAST"
+! RUN: %flang_fc1 -emit-fir -mllvm -outline-intrinsics -mllvm --force-mlir-complex %s -o - | FileCheck %s --check-prefixes="CMPLX,CMPLX-FAST,CMPLX-MLIR"
+! RUN: %flang_fc1 -fapprox-func -emit-fir -mllvm -outline-intrinsics %s -o - | FileCheck %s --check-prefixes="CMPLX,CMPLX-FAST,CMPLX-APPROX"
 
 ! CHECK-LABEL: log_testr
 ! CHECK-SAME: (%[[AREF:.*]]: !fir.ref<f32> {{.*}}, %[[BREF:.*]]: !fir.ref<f32> {{.*}})
@@ -76,8 +76,9 @@ end subroutine
 ! CHECK: %[[RESULT64_OUTLINE:.*]] = math.log %[[ARG64_OUTLINE]] fastmath<contract> : f64
 ! CHECK: return %[[RESULT64_OUTLINE]] : f64
 
-! CMPLX-FAST-LABEL: private @fir.log.contract_afn.z4.z4
+! CMPLX-APPROX-LABEL: private @fir.log.contract_afn.z4.z4
 ! CMPLX-PRECISE-LABEL: private @fir.log.contract.z4.z4
+! CMPLX-MLIR-LABEL: private @fir.log.contract.z4.z4
 ! CMPLX-SAME: (%[[ARG32_OUTLINE:.*]]: !fir.complex<4>) -> !fir.complex<4>
 ! CMPLX-FAST: %[[C:.*]] = fir.convert %[[ARG32_OUTLINE]] : (!fir.complex<4>) -> complex<f32>
 ! CMPLX-FAST: %[[E:.*]] = complex.log %[[C]] : complex<f32>
@@ -85,8 +86,9 @@ end subroutine
 ! CMPLX-PRECISE: %[[RESULT32_OUTLINE:.*]] = fir.call @clogf(%[[ARG32_OUTLINE]]) fastmath<contract> : (!fir.complex<4>) -> !fir.complex<4>
 ! CMPLX: return %[[RESULT32_OUTLINE]] : !fir.complex<4>
 
-! CMPLX-FAST-LABEL: private @fir.log.contract_afn.z8.z8
+! CMPLX-APPROX-LABEL: private @fir.log.contract_afn.z8.z8
 ! CMPLX-PRECISE-LABEL: private @fir.log.contract.z8.z8
+! CMPLX-MLIR-LABEL: private @fir.log.contract.z8.z8
 ! CMPLX-SAME: (%[[ARG64_OUTLINE:.*]]: !fir.complex<8>) -> !fir.complex<8>
 ! CMPLX-FAST: %[[C:.*]] = fir.convert %[[ARG64_OUTLINE]] : (!fir.complex<8>) -> complex<f64>
 ! CMPLX-FAST: %[[E:.*]] = complex.log %[[C]] : complex<f64>
diff --git a/flang/test/Lower/power-operator.f90 b/flang/test/Lower/power-operator.f90
index 7b80bf4..7436e03 100644
--- a/flang/test/Lower/power-operator.f90
+++ b/flang/test/Lower/power-operator.f90
@@ -1,10 +1,10 @@
 ! RUN: bbc -emit-fir %s -o - | FileCheck %s --check-prefixes="CHECK,PRECISE"
 ! RUN: bbc --math-runtime=precise -emit-fir %s -o - | FileCheck %s --check-prefixes="PRECISE"
-! RUN: bbc --disable-mlir-complex -emit-fir %s -o - | FileCheck %s --check-prefixes="PRECISE"
+! RUN: bbc --force-mlir-complex -emit-fir %s -o - | FileCheck %s --check-prefixes="FAST"
 ! RUN: %flang_fc1 -emit-fir %s -o - | FileCheck %s --check-prefixes="CHECK,PRECISE"
 ! RUN: %flang_fc1 -fapprox-func -emit-fir %s -o - | FileCheck %s --check-prefixes="CHECK,FAST"
 ! RUN: %flang_fc1 -emit-fir -mllvm --math-runtime=precise %s -o - | FileCheck %s --check-prefixes="PRECISE"
-! RUN: %flang_fc1 -emit-fir -mllvm --disable-mlir-complex %s -o - | FileCheck %s --check-prefixes="PRECISE"
+! RUN: %flang_fc1 -emit-fir -mllvm --force-mlir-complex %s -o - | FileCheck %s --check-prefixes="FAST"
 
 ! Test power operation lowering
 
diff --git a/flang/test/Lower/sqrt.f90 b/flang/test/Lower/sqrt.f90
index 91cdb91..458a83b 100644
--- a/flang/test/Lower/sqrt.f90
+++ b/flang/test/Lower/sqrt.f90
@@ -1,10 +1,10 @@
 ! RUN: bbc -emit-fir -outline-intrinsics %s -o - | FileCheck %s --check-prefixes="CHECK,CMPLX-PRECISE"
 ! RUN: bbc --math-runtime=precise -emit-fir -outline-intrinsics %s -o - | FileCheck %s --check-prefixes="CMPLX-PRECISE"
-! RUN: bbc --disable-mlir-complex -emit-fir -outline-intrinsics %s -o - | FileCheck %s --check-prefixes="CMPLX-PRECISE"
+! RUN: bbc --force-mlir-complex -emit-fir -outline-intrinsics %s -o - | FileCheck %s --check-prefixes="CMPLX-FAST"
 ! RUN: %flang_fc1 -emit-fir -mllvm -outline-intrinsics %s -o - | FileCheck %s --check-prefixes="CHECK,CMPLX-PRECISE"
 ! RUN: %flang_fc1 -fapprox-func -emit-fir -mllvm -outline-intrinsics %s -o - | FileCheck %s --check-prefixes="CMPLX-FAST"
 ! RUN: %flang_fc1 -emit-fir -mllvm --math-runtime=precise -mllvm -outline-intrinsics %s -o - | FileCheck %s --check-prefixes="CMPLX-PRECISE"
-! RUN: %flang_fc1 -emit-fir -mllvm --disable-mlir-complex -mllvm -outline-intrinsics %s -o - | FileCheck %s --check-prefixes="CMPLX-PRECISE"
+! RUN: %flang_fc1 -emit-fir -mllvm --force-mlir-complex -mllvm -outline-intrinsics %s -o - | FileCheck %s --check-prefixes="CMPLX-FAST"
 
 ! CHECK-LABEL: sqrt_testr
 subroutine sqrt_testr(a, b)