[clang] 15a1780 - [PowerPC] Replace subtract-from-zero float in version with fneg in PowerPC special fma compiler builtins

Kevin P. Neal via cfe-commits cfe-commits at lists.llvm.org
Wed Jun 3 06:45:38 PDT 2020


Author: Andrew Wock
Date: 2020-06-03T09:45:27-04:00
New Revision: 15a1780a10e3ba4573b8c1e02e24d3f0a785e199

URL: https://github.com/llvm/llvm-project/commit/15a1780a10e3ba4573b8c1e02e24d3f0a785e199
DIFF: https://github.com/llvm/llvm-project/commit/15a1780a10e3ba4573b8c1e02e24d3f0a785e199.diff

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

This is a re-revert with a corrected test.

This patch adds a test for the PowerPC fma compiler builtins, some variations
of which negate inputs and outputs. The code to generate IR for these
builtins was untested before this patch.

Originally, the code used the outdated method of subtracting floating point
values from -0.0 as floating point negation. This patch remedies that.

Patch by: Drew Wock <drew.wock at sas.com>
Differential Revision: https://reviews.llvm.org/D76949

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

Modified: 
    clang/lib/CodeGen/CGBuiltin.cpp
    clang/test/CodeGen/builtins-ppc-vsx.c

Removed: 
    


################################################################################
diff  --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp
index 13c24a5d2686..948d31312bd8 100644
--- a/clang/lib/CodeGen/CGBuiltin.cpp
+++ b/clang/lib/CodeGen/CGBuiltin.cpp
@@ -14056,7 +14056,6 @@ 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:
@@ -14064,17 +14063,14 @@ Value *CodeGenFunction::EmitPPCBuiltinExpr(unsigned BuiltinID,
         return Builder.CreateCall(F, {X, Y, Z});
       case PPC::BI__builtin_vsx_xvnmaddadp:
       case PPC::BI__builtin_vsx_xvnmaddasp:
-        return Builder.CreateFSub(Zero,
-                                  Builder.CreateCall(F, {X, Y, Z}), "sub");
+        return Builder.CreateFNeg(Builder.CreateCall(F, {X, Y, Z}), "neg");
       case PPC::BI__builtin_vsx_xvmsubadp:
       case PPC::BI__builtin_vsx_xvmsubasp:
-        return Builder.CreateCall(F,
-                                  {X, Y, Builder.CreateFSub(Zero, Z, "sub")});
+        return Builder.CreateCall(F, {X, Y, Builder.CreateFNeg(Z, "neg")});
       case PPC::BI__builtin_vsx_xvnmsubadp:
       case PPC::BI__builtin_vsx_xvnmsubasp:
-        Value *FsubRes =
-          Builder.CreateCall(F, {X, Y, Builder.CreateFSub(Zero, Z, "sub")});
-        return Builder.CreateFSub(Zero, FsubRes, "sub");
+        return Builder.CreateFNeg(
+            Builder.CreateCall(F, {X, Y, Builder.CreateFNeg(Z, "neg")}), "neg");
     }
     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
new file mode 100644
index 000000000000..3f124e8c8299
--- /dev/null
+++ b/clang/test/CodeGen/builtins-ppc-fma.c
@@ -0,0 +1,43 @@
+// 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: [[RESULT:%[^ ]+]] = fneg <2 x double> %{{.*}}
+  // CHECK: <2 x double> @llvm.fma.v2f64(<2 x double> %{{.*}}, <2 x double> %{{.*}}, <2 x double> [[RESULT]])
+
+  vf = __builtin_vsx_xvnmsubasp(vf, vf, vf);
+  // CHECK: [[RESULT:%[^ ]+]] = fneg <4 x float> %{{.*}}
+  // CHECK: [[RESULT2:%[^ ]+]] = call <4 x float> @llvm.fma.v4f32(<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]]
+}

diff  --git a/clang/test/CodeGen/builtins-ppc-vsx.c b/clang/test/CodeGen/builtins-ppc-vsx.c
index a19e75518a8d..0d0724726275 100644
--- a/clang/test/CodeGen/builtins-ppc-vsx.c
+++ b/clang/test/CodeGen/builtins-ppc-vsx.c
@@ -713,15 +713,15 @@ void test1() {
 
   /* vec_msub */
   res_vf = vec_msub(vf, vf, vf);
-// CHECK: fsub <4 x float> <float -0.000000e+00, float -0.000000e+00, float -0.000000e+00, float -0.000000e+00>, %{{[0-9]+}}
+// CHECK: fneg <4 x float> %{{[0-9]+}}
 // CHECK-NEXT: call <4 x float> @llvm.fma.v4f32(<4 x float> %{{[0-9]+}}, <4 x float> %{{[0-9]+}}, <4 x float>
-// CHECK-LE: fsub <4 x float> <float -0.000000e+00, float -0.000000e+00, float -0.000000e+00, float -0.000000e+00>, %{{[0-9]+}}
+// CHECK-LE: fneg <4 x float> %{{[0-9]+}}
 // CHECK-LE-NEXT: call <4 x float> @llvm.fma.v4f32(<4 x float> %{{[0-9]+}}, <4 x float> %{{[0-9]+}}, <4 x float>
 
   res_vd = vec_msub(vd, vd, vd);
-// CHECK: fsub <2 x double> <double -0.000000e+00, double -0.000000e+00>, %{{[0-9]+}}
+// CHECK: fneg <2 x double> %{{[0-9]+}}
 // CHECK-NEXT: call <2 x double> @llvm.fma.v2f64(<2 x double> %{{[0-9]+}}, <2 x double> %{{[0-9]+}}, <2 x double>
-// CHECK-LE: fsub <2 x double> <double -0.000000e+00, double -0.000000e+00>, %{{[0-9]+}}
+// CHECK-LE: fneg <2 x double> %{{[0-9]+}}
 // CHECK-LE-NEXT: call <2 x double> @llvm.fma.v2f64(<2 x double> %{{[0-9]+}}, <2 x double> %{{[0-9]+}}, <2 x double>
 
   res_vsll = vec_mul(vsll, vsll);
@@ -750,31 +750,31 @@ void test1() {
 
   res_vf = vec_nmadd(vf, vf, vf);
 // CHECK: [[FM:[0-9]+]] = call <4 x float> @llvm.fma.v4f32(<4 x float> %{{[0-9]+}}, <4 x float> %{{[0-9]+}}, <4 x float> %{{[0-9]+}})
-// CHECK-NEXT: fsub <4 x float> <float -0.000000e+00, float -0.000000e+00, float -0.000000e+00, float -0.000000e+00>, %[[FM]]
+// CHECK-NEXT: fneg <4 x float> %[[FM]]
 // CHECK-LE: [[FM:[0-9]+]] = call <4 x float> @llvm.fma.v4f32(<4 x float> %{{[0-9]+}}, <4 x float> %{{[0-9]+}}, <4 x float> %{{[0-9]+}})
-// CHECK-LE-NEXT: fsub <4 x float> <float -0.000000e+00, float -0.000000e+00, float -0.000000e+00, float -0.000000e+00>, %[[FM]]
+// CHECK-LE-NEXT: fneg <4 x float> %[[FM]]
 
   res_vd = vec_nmadd(vd, vd, vd);
 // CHECK: [[FM:[0-9]+]] = call <2 x double> @llvm.fma.v2f64(<2 x double> %{{[0-9]+}}, <2 x double> %{{[0-9]+}}, <2 x double> %{{[0-9]+}})
-// CHECK-NEXT: fsub <2 x double> <double -0.000000e+00, double -0.000000e+00>, %[[FM]]
+// CHECK-NEXT: fneg <2 x double> %[[FM]]
 // CHECK-LE: [[FM:[0-9]+]] = call <2 x double> @llvm.fma.v2f64(<2 x double> %{{[0-9]+}}, <2 x double> %{{[0-9]+}}, <2 x double> %{{[0-9]+}})
-// CHECK-LE-NEXT: fsub <2 x double> <double -0.000000e+00, double -0.000000e+00>, %[[FM]]
+// CHECK-LE-NEXT: fneg <2 x double> %[[FM]]
 
   res_vf = vec_nmsub(vf, vf, vf);
-// CHECK: fsub <4 x float> <float -0.000000e+00, float -0.000000e+00, float -0.000000e+00, float -0.000000e+00>, %{{[0-9]+}}
+// CHECK: fneg <4 x float> %{{[0-9]+}}
 // CHECK-NEXT: call <4 x float> @llvm.fma.v4f32(<4 x float> %{{[0-9]+}}, <4 x float> %{{[0-9]+}}, <4 x float>
-// CHECK: fsub <4 x float> <float -0.000000e+00, float -0.000000e+00, float -0.000000e+00, float -0.000000e+00>, %{{[0-9]+}}
-// CHECK-LE: fsub <4 x float> <float -0.000000e+00, float -0.000000e+00, float -0.000000e+00, float -0.000000e+00>, %{{[0-9]+}}
+// CHECK: fneg <4 x float> %{{[0-9]+}}
+// CHECK-LE: fneg <4 x float> %{{[0-9]+}}
 // CHECK-LE-NEXT: call <4 x float> @llvm.fma.v4f32(<4 x float> %{{[0-9]+}}, <4 x float> %{{[0-9]+}}, <4 x float>
-// CHECK-LE: fsub <4 x float> <float -0.000000e+00, float -0.000000e+00, float -0.000000e+00, float -0.000000e+00>, %{{[0-9]+}}
+// CHECK-LE: fneg <4 x float> %{{[0-9]+}}
 
   res_vd = vec_nmsub(vd, vd, vd);
-// CHECK: fsub <2 x double> <double -0.000000e+00, double -0.000000e+00>, %{{[0-9]+}}
+// CHECK: fneg <2 x double> %{{[0-9]+}}
 // CHECK-NEXT: [[FM:[0-9]+]] = call <2 x double> @llvm.fma.v2f64(<2 x double> %{{[0-9]+}}, <2 x double> %{{[0-9]+}}, <2 x double>
-// CHECK-NEXT: fsub <2 x double> <double -0.000000e+00, double -0.000000e+00>, %[[FM]]
-// CHECK-LE: fsub <2 x double> <double -0.000000e+00, double -0.000000e+00>, %{{[0-9]+}}
+// CHECK-NEXT: fneg <2 x double> %[[FM]]
+// CHECK-LE: fneg <2 x double> %{{[0-9]+}}
 // CHECK-LE-NEXT: [[FM:[0-9]+]] = call <2 x double> @llvm.fma.v2f64(<2 x double> %{{[0-9]+}}, <2 x double> %{{[0-9]+}}, <2 x double>
-// CHECK-LE-NEXT: fsub <2 x double> <double -0.000000e+00, double -0.000000e+00>, %[[FM]]
+// CHECK-LE-NEXT: fneg <2 x double> %[[FM]]
 
   /* vec_nor */
   res_vsll = vec_nor(vsll, vsll);


        


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