From 6797a3a1e0b3ad9f5df62e2b751c8d5ac50cbaf5 Mon Sep 17 00:00:00 2001
From: Martin Kroeker <martin@ruby.chemie.uni-freiburg.de>
Date: Thu, 27 Aug 2020 11:15:12 +0200
Subject: [PATCH] Add early returns

---
 relapack/src/cgetrf.c      | 9 +++++++--
 relapack/src/chegst.c      | 2 ++
 relapack/src/chetrf_rook.c | 4 ++--
 relapack/src/clauum.c      | 2 ++
 relapack/src/cpotrf.c      | 3 +++
 relapack/src/csytrf.c      | 3 ++-
 relapack/src/csytrf_rook.c | 4 ++--
 relapack/src/ctgsyl.c      | 7 +++++++
 relapack/src/ctrsyl.c      | 5 +++++
 relapack/src/ctrtri.c      | 2 ++
 10 files changed, 34 insertions(+), 7 deletions(-)

diff --git a/relapack/src/cgetrf.c b/relapack/src/cgetrf.c
index 878c9ec15..bf9ca53f4 100644
--- a/relapack/src/cgetrf.c
+++ b/relapack/src/cgetrf.c
@@ -30,6 +30,8 @@ void RELAPACK_cgetrf(
         return;
     }
 
+    if (*m == 0 || *n == 0) return;
+
     const blasint sn = MIN(*m, *n);
 
     RELAPACK_cgetrf_rec(m, &sn, A, ldA, ipiv, info);
@@ -62,9 +64,11 @@ static void RELAPACK_cgetrf_rec(
     blasint *info
 ) {
 
-    if (*n <= MAX(CROSSOVER_CGETRF, 1)) {
+    if (*m == 0 || *n == 0) return;
+
+    if ( *n <= MAX(CROSSOVER_CGETRF, 1)) {
         // Unblocked
-        LAPACK(cgetf2)(m, n, A, ldA, ipiv, info);
+        LAPACK(cgetrf2)(m, n, A, ldA, ipiv, info);
         return;
     }
 
@@ -96,6 +100,7 @@ static void RELAPACK_cgetrf_rec(
 
     // recursion(A_L, ipiv_T)
     RELAPACK_cgetrf_rec(m, &n1, A_L, ldA, ipiv_T, info);
+    if (*info) return;
     // apply pivots to A_R
     LAPACK(claswp)(&n2, A_R, ldA, iONE, &n1, ipiv_T, iONE);
 
diff --git a/relapack/src/chegst.c b/relapack/src/chegst.c
index fe77b03ea..8557c2952 100644
--- a/relapack/src/chegst.c
+++ b/relapack/src/chegst.c
@@ -40,6 +40,8 @@ void RELAPACK_chegst(
         return;
     }
 
+    if (*n == 0) return;
+
     // Clean char * arguments
     const char cleanuplo = lower ? 'L' : 'U';
 
diff --git a/relapack/src/chetrf_rook.c b/relapack/src/chetrf_rook.c
index 3d2fa3216..9ed1261cf 100644
--- a/relapack/src/chetrf_rook.c
+++ b/relapack/src/chetrf_rook.c
@@ -36,7 +36,7 @@ void RELAPACK_chetrf_rook(
         *info = -2;
     else if (*ldA < MAX(1, *n))
         *info = -4;
-    else if (*lWork < minlWork && *lWork != -1)
+    else if ((*lWork < 1 || *lWork < minlWork) && *lWork != -1)
         *info = -7;
     else if (*lWork == -1) {
         // Work size query
@@ -56,7 +56,7 @@ void RELAPACK_chetrf_rook(
 
     if (*info) {
         const blasint minfo = -*info;
-        LAPACK(xerbla)("CHETRF", &minfo, strlen("CHETRF"));
+        LAPACK(xerbla)("CHETRF_ROOK", &minfo, strlen("CHETRF_ROOK"));
         return;
     }
 
diff --git a/relapack/src/clauum.c b/relapack/src/clauum.c
index 2bc93f182..58a14e7da 100644
--- a/relapack/src/clauum.c
+++ b/relapack/src/clauum.c
@@ -32,6 +32,8 @@ void RELAPACK_clauum(
         return;
     }
 
+    if (*n == 0) return;
+
     // Clean char * arguments
     const char cleanuplo = lower ? 'L' : 'U';
 
diff --git a/relapack/src/cpotrf.c b/relapack/src/cpotrf.c
index 0f8e7ebb0..db06c6fef 100644
--- a/relapack/src/cpotrf.c
+++ b/relapack/src/cpotrf.c
@@ -32,6 +32,8 @@ void RELAPACK_cpotrf(
         return;
     }
 
+    if (*n == 0) return;
+
     // Clean char * arguments
     const char cleanuplo = lower ? 'L' : 'U';
 
@@ -46,6 +48,7 @@ static void RELAPACK_cpotrf_rec(
     float *A, const blasint *ldA,
     blasint *info
 ){
+    if (*n == 0) return;
 
     if (*n <= MAX(CROSSOVER_CPOTRF, 1)) {
         // Unblocked
diff --git a/relapack/src/csytrf.c b/relapack/src/csytrf.c
index 2ebc31001..807c91ece 100644
--- a/relapack/src/csytrf.c
+++ b/relapack/src/csytrf.c
@@ -36,7 +36,7 @@ void RELAPACK_csytrf(
         *info = -2;
     else if (*ldA < MAX(1, *n))
         *info = -4;
-    else if (*lWork < minlWork && *lWork != -1)
+    else if ((*lWork < 1 || *lWork < minlWork) && *lWork != -1)
         *info = -7;
     else if (*lWork == -1) {
         // Work size query
@@ -67,6 +67,7 @@ void RELAPACK_csytrf(
     blasint nout;
 
     // Recursive kernel
+if (*n != 0)
     RELAPACK_csytrf_rec(&cleanuplo, n, n, &nout, A, ldA, ipiv, cleanWork, n, info);
 
 #if XSYTRF_ALLOW_MALLOC
diff --git a/relapack/src/csytrf_rook.c b/relapack/src/csytrf_rook.c
index e8a9865cc..105c6b8b6 100644
--- a/relapack/src/csytrf_rook.c
+++ b/relapack/src/csytrf_rook.c
@@ -36,7 +36,7 @@ void RELAPACK_csytrf_rook(
         *info = -2;
     else if (*ldA < MAX(1, *n))
         *info = -4;
-    else if (*lWork < minlWork && *lWork != -1)
+    else if ((*lWork < 1 || *lWork < minlWork) && *lWork != -1)
         *info = -7;
     else if (*lWork == -1) {
         // Work size query
@@ -56,7 +56,7 @@ void RELAPACK_csytrf_rook(
 
     if (*info) {
         const blasint minfo = -*info;
-        LAPACK(xerbla)("CSYTRF", &minfo, strlen("CSYTRF"));
+        LAPACK(xerbla)("CSYTRF_ROOK", &minfo, strlen("CSYTRF_ROOK"));
         return;
     }
 
diff --git a/relapack/src/ctgsyl.c b/relapack/src/ctgsyl.c
index 704f3ef23..632bbc14e 100644
--- a/relapack/src/ctgsyl.c
+++ b/relapack/src/ctgsyl.c
@@ -68,6 +68,13 @@ void RELAPACK_ctgsyl(
         return;
     }
 
+    if ( *m == 0 || *n == 0) {
+      *scale = 1.;
+      if (notran && (*ijob != 0))
+        *dif = 0.;
+      return;
+    }
+
     // Clean char * arguments
     const char cleantrans = notran ? 'N' : 'C';
 
diff --git a/relapack/src/ctrsyl.c b/relapack/src/ctrsyl.c
index fed6e847e..f7b841cb0 100644
--- a/relapack/src/ctrsyl.c
+++ b/relapack/src/ctrsyl.c
@@ -47,6 +47,11 @@ void RELAPACK_ctrsyl(
         return;
     }
 
+    if (*m == 0 || *n == 0) {
+      *scale = 1.;
+      return;
+    }
+
     // Clean char * arguments
     const char cleantranA = notransA ? 'N' : 'C';
     const char cleantranB = notransB ? 'N' : 'C';
diff --git a/relapack/src/ctrtri.c b/relapack/src/ctrtri.c
index 5201a24c7..8d736007b 100644
--- a/relapack/src/ctrtri.c
+++ b/relapack/src/ctrtri.c
@@ -36,6 +36,8 @@ void RELAPACK_ctrtri(
         return;
     }
 
+    if (*n == 0) return;
+
     // Clean char * arguments
     const char cleanuplo = lower  ? 'L' : 'U';
     const char cleandiag = nounit ? 'N' : 'U';