r252307 - Fix __builtin_signbit for ppcf128 type
Petar Jovanovic via cfe-commits
cfe-commits at lists.llvm.org
Fri Nov 6 06:52:46 PST 2015
Author: petarj
Date: Fri Nov 6 08:52:46 2015
New Revision: 252307
URL: http://llvm.org/viewvc/llvm-project?rev=252307&view=rev
Log:
Fix __builtin_signbit for ppcf128 type
Function__builtin_signbit returns wrong value for type ppcf128 on big endian
machines. This patch fixes how value is generated in that case.
Patch by Aleksandar Beserminji.
Differential Revision: http://reviews.llvm.org/D14149
Added:
cfe/trunk/test/Analysis/builtin_signbit.cpp
Modified:
cfe/trunk/lib/CodeGen/CGBuiltin.cpp
Modified: cfe/trunk/lib/CodeGen/CGBuiltin.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGBuiltin.cpp?rev=252307&r1=252306&r2=252307&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGBuiltin.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGBuiltin.cpp Fri Nov 6 08:52:46 2015
@@ -238,10 +238,20 @@ static Value *EmitSignBit(CodeGenFunctio
llvm::Type *IntTy = llvm::IntegerType::get(C, Width);
V = CGF.Builder.CreateBitCast(V, IntTy);
if (Ty->isPPC_FP128Ty()) {
- // The higher-order double comes first, and so we need to truncate the
- // pair to extract the overall sign. The order of the pair is the same
- // in both little- and big-Endian modes.
+ // We want the sign bit of the higher-order double. The bitcast we just
+ // did works as if the double-double was stored to memory and then
+ // read as an i128. The "store" will put the higher-order double in the
+ // lower address in both little- and big-Endian modes, but the "load"
+ // will treat those bits as a different part of the i128: the low bits in
+ // little-Endian, the high bits in big-Endian. Therefore, on big-Endian
+ // we need to shift the high bits down to the low before truncating.
Width >>= 1;
+ if (CGF.getTarget().isBigEndian()) {
+ Value *ShiftCst = llvm::ConstantInt::get(IntTy, Width);
+ V = CGF.Builder.CreateLShr(V, ShiftCst);
+ }
+ // We are truncating value in order to extract the higher-order
+ // double, which we will be using to extract the sign from.
IntTy = llvm::IntegerType::get(C, Width);
V = CGF.Builder.CreateTrunc(V, IntTy);
}
Added: cfe/trunk/test/Analysis/builtin_signbit.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Analysis/builtin_signbit.cpp?rev=252307&view=auto
==============================================================================
--- cfe/trunk/test/Analysis/builtin_signbit.cpp (added)
+++ cfe/trunk/test/Analysis/builtin_signbit.cpp Fri Nov 6 08:52:46 2015
@@ -0,0 +1,43 @@
+// RUN: %clang -target powerpc-linux-gnu -emit-llvm -S -O0 %s -o - | FileCheck %s --check-prefix=CHECK-BE --check-prefix=CHECK
+// RUN: %clang -target powerpc64-linux-gnu -emit-llvm -S -O0 %s -o - | FileCheck %s --check-prefix=CHECK-BE --check-prefix=CHECK
+// RUN: %clang -target powerpc64le-linux-gnu -emit-llvm -S -O0 %s -o - | FileCheck %s --check-prefix=CHECK-LE --check-prefix=CHECK
+
+bool b;
+double d = -1.0;
+long double ld = -1.0L;
+void test_signbit()
+{
+ b = __builtin_signbit(1.0L);
+ // CHECK: i128
+ // CHECK-LE-NOT: lshr
+ // CHECK-BE: lshr
+ // CHECK: bitcast
+ // CHECK: ppc_fp128
+
+ b = __builtin_signbit(ld);
+ // CHECK: bitcast
+ // CHECK: ppc_fp128
+ // CHECK-LE-NOT: lshr
+ // CHECK-BE: lshr
+
+ b = __builtin_signbitf(1.0);
+ // CHECK: store i8 0
+
+ b = __builtin_signbitf(d);
+ // CHECK: bitcast
+ // CHECK-LE-NOT: lshr
+ // CHECK-BE-NOT: lshr
+
+ b = __builtin_signbitl(1.0L);
+ // CHECK: i128
+ // CHECK-LE-NOT: lshr
+ // CHECK-BE: lshr
+ // CHECK: bitcast
+ // CHECK: ppc_fp128
+
+ b = __builtin_signbitl(ld);
+ // CHECK: bitcast
+ // CHECK: ppc_fp128
+ // CHECK-LE-NOT: lshr
+ // CHECK-BE: lshr
+}
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