From 3e40b08ba005643bd0190fe45437a82404519c16 Mon Sep 17 00:00:00 2001
From: Ayke van Laethem <aykevanlaethem@gmail.com>
Date: Wed, 28 Oct 2020 00:49:13 +0100
Subject: [PATCH] compiler: implement negate for complex numbers

---
 compiler/compiler.go | 10 ++++++++++
 testdata/float.go    |  4 +++-
 testdata/float.txt   |  2 ++
 3 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/compiler/compiler.go b/compiler/compiler.go
index 4a42bc69..1992fee6 100644
--- a/compiler/compiler.go
+++ b/compiler/compiler.go
@@ -2581,6 +2581,16 @@ func (b *builder) createUnOp(unop *ssa.UnOp) (llvm.Value, error) {
 				return b.CreateSub(llvm.ConstInt(x.Type(), 0, false), x, ""), nil
 			} else if typ.Info()&types.IsFloat != 0 {
 				return b.CreateFNeg(x, ""), nil
+			} else if typ.Info()&types.IsComplex != 0 {
+				// Negate both components of the complex number.
+				r := b.CreateExtractValue(x, 0, "r")
+				i := b.CreateExtractValue(x, 1, "i")
+				r = b.CreateFNeg(r, "")
+				i = b.CreateFNeg(i, "")
+				cplx := llvm.Undef(x.Type())
+				cplx = b.CreateInsertValue(cplx, r, 0, "")
+				cplx = b.CreateInsertValue(cplx, i, 1, "")
+				return cplx, nil
 			} else {
 				return llvm.Value{}, b.makeError(unop.Pos(), "todo: unknown basic type for negate: "+typ.String())
 			}
diff --git a/testdata/float.go b/testdata/float.go
index f2b7c52e..8c33cf11 100644
--- a/testdata/float.go
+++ b/testdata/float.go
@@ -57,15 +57,17 @@ func main() {
 	println(complex64(c128))
 	println(complex128(c64))
 
-	// binops on complex numbers
+	// binops and negate on complex numbers
 	c64 = 5 + 2i
 	println("complex64 add: ", c64+-3+8i)
 	println("complex64 sub: ", c64 - -3 + 8i)
 	println("complex64 mul: ", c64*-3+8i)
 	println("complex64 div: ", c64/-3+8i)
+	println("complex64 neg: ", -c64)
 	c128 = -5 + 2i
 	println("complex128 add:", c128+2+6i)
 	println("complex128 sub:", c128-2+6i)
 	println("complex128 mul:", c128*2+6i)
 	println("complex128 div:", c128/2+6i)
+	println("complex128 neg:", -c128)
 }
diff --git a/testdata/float.txt b/testdata/float.txt
index 4b7e3357..dbc36fb8 100644
--- a/testdata/float.txt
+++ b/testdata/float.txt
@@ -27,7 +27,9 @@ complex64 add:  (+2.000000e+000+1.000000e+001i)
 complex64 sub:  (+8.000000e+000+1.000000e+001i)
 complex64 mul:  (-1.500000e+001+2.000000e+000i)
 complex64 div:  (-1.666667e+000+7.333333e+000i)
+complex64 neg:  (-5.000000e+000-2.000000e+000i)
 complex128 add: (-3.000000e+000+8.000000e+000i)
 complex128 sub: (-7.000000e+000+8.000000e+000i)
 complex128 mul: (-1.000000e+001+1.000000e+001i)
 complex128 div: (-2.500000e+000+7.000000e+000i)
+complex128 neg: (+5.000000e+000-2.000000e+000i)