[clang] 9f1c35d - Revert "[PowerPC] Replace subtract-from-zero float in version with fneg in PowerPC special fma compiler builtins"

[Kevin P. Neal via cfe-commits]

Author: Kevin P. Neal
Date: 2020-04-03T15:47:19-04:00
New Revision: 9f1c35d8b14f026b7bc4b21b9eecafbbb42c42a2

URL: https://github.com/llvm/llvm-project/commit/9f1c35d8b14f026b7bc4b21b9eecafbbb42c42a2
DIFF: https://github.com/llvm/llvm-project/commit/9f1c35d8b14f026b7bc4b21b9eecafbbb42c42a2.diff

LOG: Revert "[PowerPC] Replace subtract-from-zero float in version with fneg in PowerPC special fma compiler builtins"

The new test case causes bot failures.

This reverts commit ba87430cadb2d5d0ee8e4b75101d7abcf6b321bf.

Added: 
    

Modified: 
    clang/lib/CodeGen/CGBuiltin.cpp

Removed: 
    clang/test/CodeGen/builtins-ppc-fma.c


################################################################################
diff  --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp
index 3545ccda5d4d..880fe0e271f5 100644
--- a/clang/lib/CodeGen/CGBuiltin.cpp
+++ b/clang/lib/CodeGen/CGBuiltin.cpp
@@ -13214,24 +13214,25 @@ Value *CodeGenFunction::EmitPPCBuiltinExpr(unsigned BuiltinID,
     Value *X = EmitScalarExpr(E->getArg(0));
     Value *Y = EmitScalarExpr(E->getArg(1));
     Value *Z = EmitScalarExpr(E->getArg(2));
+    Value *Zero = llvm::ConstantFP::getZeroValueForNegation(ResultType);
     llvm::Function *F = CGM.getIntrinsic(Intrinsic::fma, ResultType);
     switch (BuiltinID) {
       case PPC::BI__builtin_vsx_xvmaddadp:
       case PPC::BI__builtin_vsx_xvmaddasp:
         return Builder.CreateCall(F, {X, Y, Z});
-
       case PPC::BI__builtin_vsx_xvnmaddadp:
       case PPC::BI__builtin_vsx_xvnmaddasp:
-        return Builder.CreateFNeg(Builder.CreateCall(F, {X, Y, Z}), "neg");
-
+        return Builder.CreateFSub(Zero,
+                                  Builder.CreateCall(F, {X, Y, Z}), "sub");
       case PPC::BI__builtin_vsx_xvmsubadp:
       case PPC::BI__builtin_vsx_xvmsubasp:
-        return Builder.CreateCall(F, {X, Y, Builder.CreateFNeg(Z, "neg")});
-
+        return Builder.CreateCall(F,
+                                  {X, Y, Builder.CreateFSub(Zero, Z, "sub")});
       case PPC::BI__builtin_vsx_xvnmsubadp:
       case PPC::BI__builtin_vsx_xvnmsubasp:
-        return Builder.CreateFNeg(
-            Builder.CreateCall(F, {X, Y, Builder.CreateFNeg(Z, "neg")}), "neg");
+        Value *FsubRes =
+          Builder.CreateCall(F, {X, Y, Builder.CreateFSub(Zero, Z, "sub")});
+        return Builder.CreateFSub(Zero, FsubRes, "sub");
     }
     llvm_unreachable("Unknown FMA operation");
     return nullptr; // Suppress no-return warning

diff  --git a/clang/test/CodeGen/builtins-ppc-fma.c b/clang/test/CodeGen/builtins-ppc-fma.c
deleted file mode 100644
index e91b45b0daa7..000000000000
--- a/clang/test/CodeGen/builtins-ppc-fma.c
+++ /dev/null
@@ -1,43 +0,0 @@
-// RUN: %clang_cc1 -triple powerpc64le-gnu-linux \
-// RUN: -target-feature +altivec -Wall -Wno-unused -Werror -emit-llvm %s -o - | FileCheck      \
-// RUN: %s
-
-typedef __attribute__((vector_size(4 * sizeof(float)))) float vec_float;
-typedef __attribute__((vector_size(2 * sizeof(double)))) double vec_double;
-
-volatile vec_double vd;
-volatile vec_float vf;
-
-void test_fma(void) {
-  vf = __builtin_vsx_xvmaddasp(vf, vf, vf);
-  // CHECK: @llvm.fma.v4f32(<4 x float> %{{.*}}, <4 x float> %{{.*}}, <4 x float> %{{.*}})
-
-  vd = __builtin_vsx_xvmaddadp(vd, vd, vd);
-  // CHECK: @llvm.fma.v2f64(<2 x double> %{{.*}}, <2 x double> %{{.*}}, <2 x double> %{{.*}})
-
-  vf = __builtin_vsx_xvnmaddasp(vf, vf, vf);
-  // CHECK: [[RESULT:%[^ ]+]] = call <4 x float> @llvm.fma.v4f32(<4 x float> %{{.*}}, <4 x float> %{{.*}}, <4 x float> %{{.*}})
-  // CHECK: fneg <4 x float> [[RESULT]]
-
-  vd = __builtin_vsx_xvnmaddadp(vd, vd, vd);
-  // CHECK: [[RESULT:%[^ ]+]] = call <2 x double> @llvm.fma.v2f64(<2 x double> %{{.*}}, <2 x double> %{{.*}}, <2 x double> %{{.*}})
-  // CHECK: fneg <2 x double> [[RESULT]]
-
-  vf = __builtin_vsx_xvmsubasp(vf, vf, vf);
-  // CHECK: [[RESULT:%[^ ]+]] = fneg <4 x float> %{{.*}}
-  // CHECK: @llvm.fma.v4f32(<4 x float> %{{.*}}, <4 x float> %{{.*}}, <4 x float> [[RESULT]])
-
-  vd = __builtin_vsx_xvmsubadp(vd, vd, vd);
-  // CHECK: fneg <2 x double> [[RESULT]]
-  // CHECK: [[RESULT:%[^ ]+]] = call <2 x double> @llvm.fma.v2f64(<2 x double> %{{.*}}, <2 x double> %{{.*}}, <2 x double> %{{.*}})
-
-  vf = __builtin_vsx_xvnmsubasp(vf, vf, vf);
-  // CHECK: [[RESULT:%[^ ]+]] = fneg <4 x float> %{{.*}}
-  // CHECK: [[RESULT2:%[^ ]+]] = call <4 x float> @llvm.fma.v2f64(<4 x float> %{{.*}}, <4 x float> %{{.*}}, <4 x float> [[RESULT]])
-  // CHECK: fneg <4 x float> [[RESULT2]]
-
-  vd = __builtin_vsx_xvnmsubadp(vd, vd, vd);
-  // CHECK: [[RESULT:%[^ ]+]] = fneg <2 x double> %{{.*}}
-  // CHECK: [[RESULT2:%[^ ]+]] = call <2 x double> @llvm.fma.v2f64(<2 x double> %{{.*}}, <2 x double> %{{.*}}, <2 x double> [[RESULT]])
-  // CHECK: fneg <2 x double> [[RESULT2]]
-}