Fix workspace query corner cases to always return at least 1 (Reference-LAPACK PR 883) (#4146)

* Fix workspace query corner cases to always return at least 1

lapack-netlib/SRC/csytrf.f

@@ -232,7 +232,7 @@
 *        Determine the block size
 *
          NB = ILAENV( 1, 'CSYTRF', UPLO, N, -1, -1, -1 )
-         LWKOPT = N*NB
+         LWKOPT = MAX( 1, N*NB )
          WORK( 1 ) = LWKOPT
       END IF
 *

lapack-netlib/SRC/csytrf_rk.f

@@ -310,7 +310,7 @@
 *        Determine the block size
 *
          NB = ILAENV( 1, 'CSYTRF_RK', UPLO, N, -1, -1, -1 )
-         LWKOPT = N*NB
+         LWKOPT = MAX( 1, N*NB )
          WORK( 1 ) = LWKOPT
       END IF
 *

lapack-netlib/SRC/ctrevc3.f

@@ -321,9 +321,9 @@
 *
       INFO = 0
       NB = ILAENV( 1, 'CTREVC', SIDE // HOWMNY, N, -1, -1, -1 )
-      MAXWRK = N + 2*N*NB
+      MAXWRK = MAX( 1, N + 2*N*NB )
       WORK(1) = MAXWRK
-      RWORK(1) = N
+      RWORK(1) = MAX( 1, N )
       LQUERY = ( LWORK.EQ.-1 .OR. LRWORK.EQ.-1 )
       IF( .NOT.RIGHTV .AND. .NOT.LEFTV ) THEN
          INFO = -1

lapack-netlib/SRC/dsytrf.f

@@ -232,7 +232,7 @@
 *        Determine the block size
 *
          NB = ILAENV( 1, 'DSYTRF', UPLO, N, -1, -1, -1 )
-         LWKOPT = N*NB
+         LWKOPT = MAX( 1, N*NB )
          WORK( 1 ) = LWKOPT
       END IF
 *

lapack-netlib/SRC/dsytrf_rk.f

@@ -310,7 +310,7 @@
 *        Determine the block size
 *
          NB = ILAENV( 1, 'DSYTRF_RK', UPLO, N, -1, -1, -1 )
-         LWKOPT = N*NB
+         LWKOPT = MAX( 1, N*NB )
          WORK( 1 ) = LWKOPT
       END IF
 *

lapack-netlib/SRC/dtrevc3.f

@@ -298,7 +298,7 @@
 *
       INFO = 0
       NB = ILAENV( 1, 'DTREVC', SIDE // HOWMNY, N, -1, -1, -1 )
-      MAXWRK = N + 2*N*NB
+      MAXWRK = MAX( 1, N + 2*N*NB )
       WORK(1) = MAXWRK
       LQUERY = ( LWORK.EQ.-1 )
       IF( .NOT.RIGHTV .AND. .NOT.LEFTV ) THEN

lapack-netlib/SRC/ssytrf.f

@@ -232,7 +232,7 @@
 *        Determine the block size
 *
          NB = ILAENV( 1, 'SSYTRF', UPLO, N, -1, -1, -1 )
-         LWKOPT = N*NB
+         LWKOPT = MAX( 1, N*NB )
          WORK( 1 ) = LWKOPT
       END IF
 *

lapack-netlib/SRC/ssytrf_rk.f

@@ -310,7 +310,7 @@
 *        Determine the block size
 *
          NB = ILAENV( 1, 'SSYTRF_RK', UPLO, N, -1, -1, -1 )
-         LWKOPT = N*NB
+         LWKOPT = MAX( 1, N*NB )
          WORK( 1 ) = LWKOPT
       END IF
 *

lapack-netlib/SRC/strevc3.f

@@ -298,7 +298,7 @@
 *
       INFO = 0
       NB = ILAENV( 1, 'STREVC', SIDE // HOWMNY, N, -1, -1, -1 )
-      MAXWRK = N + 2*N*NB
+      MAXWRK = MAX( 1, N + 2*N*NB )
       WORK(1) = MAXWRK
       LQUERY = ( LWORK.EQ.-1 )
       IF( .NOT.RIGHTV .AND. .NOT.LEFTV ) THEN

lapack-netlib/SRC/zsytrf.f

@@ -232,7 +232,7 @@
 *        Determine the block size
 *
          NB = ILAENV( 1, 'ZSYTRF', UPLO, N, -1, -1, -1 )
-         LWKOPT = N*NB
+         LWKOPT = MAX( 1, N*NB )
          WORK( 1 ) = LWKOPT
       END IF
 *

lapack-netlib/SRC/zsytrf_rk.f

@@ -310,7 +310,7 @@
 *        Determine the block size
 *
          NB = ILAENV( 1, 'ZSYTRF_RK', UPLO, N, -1, -1, -1 )
-         LWKOPT = N*NB
+         LWKOPT = MAX( 1, N*NB )
          WORK( 1 ) = LWKOPT
       END IF
 *

lapack-netlib/SRC/ztrevc3.f

@@ -321,9 +321,9 @@
 *
       INFO = 0
       NB = ILAENV( 1, 'ZTREVC', SIDE // HOWMNY, N, -1, -1, -1 )
-      MAXWRK = N + 2*N*NB
+      MAXWRK = MAX( 1, N + 2*N*NB )
       WORK(1) = MAXWRK
-      RWORK(1) = N
+      RWORK(1) = MAX( 1, N )
       LQUERY = ( LWORK.EQ.-1 .OR. LRWORK.EQ.-1 )
       IF( .NOT.RIGHTV .AND. .NOT.LEFTV ) THEN
          INFO = -1