From 6801a03911b15f84787d044f64835b5a3021ac55 Mon Sep 17 00:00:00 2001
From: Tim Besard <tim.besard@gmail.com>
Date: Wed, 10 Jun 2026 12:24:30 +0200
Subject: [PATCH] Fix symv!/hemv! and symm!/hemm! dispatch for unsupported
 eltypes.

generic_matvecmul! dispatched Symmetric inputs to symv! and Hermitian
inputs to hemv! whenever the eltype was a BLAS float, but oneMKL only
wraps symv! for real eltypes and hemv! for complex ones. Guard the
branches accordingly: complex Symmetric falls through to
generic_matmatmul! (which can use symm!), and real Hermitian uses symv!
since a real Hermitian matrix is symmetric.

Similarly, the symm!/hemm! branches in generic_matmatmul! lacked any
eltype or stridedness guards, and hemm! is only wrapped for complex
eltypes; add the missing guards and route real Hermitian to symm!.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
---
 lib/mkl/linalg.jl | 31 +++++++++++++++++++++----------
 1 file changed, 21 insertions(+), 10 deletions(-)

diff --git a/lib/mkl/linalg.jl b/lib/mkl/linalg.jl
index 287f0db7..a5ea4429 100644
--- a/lib/mkl/linalg.jl
+++ b/lib/mkl/linalg.jl
@@ -97,10 +97,15 @@ function LinearAlgebra.generic_matvecmul!(Y::oneVector, tA::AbstractChar, A::one
         if T <: onemklFloat && eltype(A) == eltype(B) == T
             if tA in ('N', 'T', 'C')
                 return gemv!(tA, alpha, A, B, beta, Y)
-            elseif tA in ('S', 's')
+            elseif tA in ('S', 's') && T <: Real
+                # complex symv! is not wrapped; fall through to generic_matmatmul!,
+                # which can use symm! instead
                 return symv!(tA == 'S' ? 'U' : 'L', alpha, A, B, beta, Y)
             elseif tA in ('H', 'h')
-                return hemv!(tA == 'H' ? 'U' : 'L', alpha, A, B, beta, Y)
+                # hemv! only supports complex eltypes, but a real Hermitian matrix
+                # is symmetric
+                fun = T <: Real ? symv! : hemv!
+                return fun(tA == 'H' ? 'U' : 'L', alpha, A, B, beta, Y)
             end
         end
     end
@@ -162,14 +167,20 @@ function LinearAlgebra.generic_matmatmul!(
                     A isa oneStridedArray{T} && B isa oneStridedArray{T}
             )
             return gemm!(tA, tB, α, A, B, β, C)
-        elseif (tA == 'S' || tA == 's') && tB == 'N'
-            return symm!('L', tA == 'S' ? 'U' : 'L', α, A, B, β, C)
-        elseif (tB == 'S' || tB == 's') && tA == 'N'
-            return symm!('R', tB == 'S' ? 'U' : 'L', α, B, A, β, C)
-        elseif (tA == 'H' || tA == 'h') && tB == 'N'
-            return hemm!('L', tA == 'H' ? 'U' : 'L', α, A, B, β, C)
-        elseif (tB == 'H' || tB == 'h') && tA == 'N'
-            return hemm!('R', tB == 'H' ? 'U' : 'L', α, B, A, β, C)
+        elseif T <: onemklFloat && A isa oneStridedArray{T} && B isa oneStridedArray{T}
+            # hemm! only supports complex eltypes, but a real Hermitian matrix
+            # is symmetric
+            if (tA == 'S' || tA == 's') && tB == 'N'
+                return symm!('L', tA == 'S' ? 'U' : 'L', α, A, B, β, C)
+            elseif (tB == 'S' || tB == 's') && tA == 'N'
+                return symm!('R', tB == 'S' ? 'U' : 'L', α, B, A, β, C)
+            elseif (tA == 'H' || tA == 'h') && tB == 'N'
+                fun = T <: Real ? symm! : hemm!
+                return fun('L', tA == 'H' ? 'U' : 'L', α, A, B, β, C)
+            elseif (tB == 'H' || tB == 'h') && tA == 'N'
+                fun = T <: Real ? symm! : hemm!
+                return fun('R', tB == 'H' ? 'U' : 'L', α, B, A, β, C)
+            end
         end
     end