Index: c-family/c-common.c
===================================================================
--- c-family/c-common.c	(revision 230930)
+++ c-family/c-common.c	(working copy)
@@ -12631,8 +12631,11 @@ maybe_warn_shift_overflow (location_t loc, tree op
 
   unsigned int min_prec = (wi::min_precision (op0, SIGNED)
 			   + TREE_INT_CST_LOW (op1));
-  /* Handle the left-shifting 1 into the sign bit case.  */
-  if (min_prec == prec0 + 1)
+  /* Handle the case of left-shifting 1 into the sign bit.
+   * However, shifting 1 _out_ of the sign bit, as in
+   * INT_MIN << 1, is considered an overflow.
+   */
+  if (!tree_int_cst_sign_bit(op0) && min_prec == prec0 + 1)
     {
       /* Never warn for C++14 onwards.  */
       if (cxx_dialect >= cxx14)
Index: testsuite/c-c++-common/Wshift-overflow-1.c
===================================================================
--- testsuite/c-c++-common/Wshift-overflow-1.c	(revision 230930)
+++ testsuite/c-c++-common/Wshift-overflow-1.c	(working copy)
@@ -8,6 +8,9 @@
 #define LLONGM1 (sizeof (long long) * __CHAR_BIT__ - 1)
 #define LLONGM2 (sizeof (long long) * __CHAR_BIT__ - 2)
 
+#define INT_MIN (-__INT_MAX__-1)
+#define LONG_LONG_MIN (-__LONG_LONG_MAX__-1)
+
 int i1 = 1 << INTM1;
 int i2 = 9 << INTM1; /* { dg-warning "requires 36 bits to represent" } */
 int i3 = 10 << INTM2; /* { dg-warning "requires 35 bits to represent" } */
@@ -18,6 +21,7 @@
 int i8 = -10 << INTM2; /* { dg-warning "requires 35 bits to represent" } */
 int i9 = -__INT_MAX__ << 2; /* { dg-warning "requires 34 bits to represent" } */
 int i10 = -__INT_MAX__ << INTM1; /* { dg-warning "requires 63 bits to represent" } */
+int i11 = INT_MIN << 1; /* { dg-warning "requires 33 bits to represent" } */
 
 int r1 = 1 >> INTM1;
 int r2 = 9 >> INTM1;
@@ -46,6 +50,7 @@
 long long int l8 = -10LL << LLONGM2; /* { dg-warning "requires 67 bits to represent" } */
 long long int l9 = -__LONG_LONG_MAX__ << 2; /* { dg-warning "requires 66 bits to represent" } */
 long long int l10 = -__LONG_LONG_MAX__ << LLONGM1; /* { dg-warning "requires 127 bits to represent" } */
+long long int l11 = LONG_LONG_MIN << 1; /* { dg-warning "requires 65 bits to represent" } */
 
 void
 fn (void)
Index: testsuite/c-c++-common/Wshift-overflow-2.c
===================================================================
--- testsuite/c-c++-common/Wshift-overflow-2.c	(revision 230930)
+++ testsuite/c-c++-common/Wshift-overflow-2.c	(working copy)
@@ -8,6 +8,9 @@
 #define LLONGM1 (sizeof (long long) * __CHAR_BIT__ - 1)
 #define LLONGM2 (sizeof (long long) * __CHAR_BIT__ - 2)
 
+#define INT_MIN (-__INT_MAX__-1)
+#define LONG_LONG_MIN (-__LONG_LONG_MAX__-1)
+
 int i1 = 1 << INTM1;
 int i2 = 9 << INTM1;
 int i3 = 10 << INTM2;
@@ -18,6 +21,7 @@
 int i8 = -10 << INTM2;
 int i9 = -__INT_MAX__ << 2;
 int i10 = -__INT_MAX__ << INTM1;
+int i11 = INT_MIN << 1;
 
 int r1 = 1 >> INTM1;
 int r2 = 9 >> INTM1;
@@ -46,6 +50,7 @@
 long long int l8 = -10LL << LLONGM2;
 long long int l9 = -__LONG_LONG_MAX__ << 2;
 long long int l10 = -__LONG_LONG_MAX__ << LLONGM1;
+long long int l11 = LONG_LONG_MIN << 1;
 
 void
 fn (void)
Index: testsuite/c-c++-common/Wshift-overflow-3.c
===================================================================
--- testsuite/c-c++-common/Wshift-overflow-3.c	(revision 230930)
+++ testsuite/c-c++-common/Wshift-overflow-3.c	(working copy)
@@ -9,6 +9,9 @@
 #define LLONGM1 (sizeof (long long) * __CHAR_BIT__ - 1)
 #define LLONGM2 (sizeof (long long) * __CHAR_BIT__ - 2)
 
+#define INT_MIN (-__INT_MAX__-1)
+#define LONG_LONG_MIN (-__LONG_LONG_MAX__-1)
+
 int i1 = 1 << INTM1;
 int i2 = 9 << INTM1; /* { dg-warning "requires 36 bits to represent" } */
 int i3 = 10 << INTM2; /* { dg-warning "requires 35 bits to represent" } */
@@ -19,6 +22,7 @@
 int i8 = -10 << INTM2; /* { dg-warning "requires 35 bits to represent" } */
 int i9 = -__INT_MAX__ << 2; /* { dg-warning "requires 34 bits to represent" } */
 int i10 = -__INT_MAX__ << INTM1; /* { dg-warning "requires 63 bits to represent" } */
+int i11 = INT_MIN << 1; /* { dg-warning "requires 33 bits to represent" } */
 
 int r1 = 1 >> INTM1;
 int r2 = 9 >> INTM1;
@@ -47,6 +51,7 @@
 long long int l8 = -10LL << LLONGM2; /* { dg-warning "requires 67 bits to represent" } */
 long long int l9 = -__LONG_LONG_MAX__ << 2; /* { dg-warning "requires 66 bits to represent" } */
 long long int l10 = -__LONG_LONG_MAX__ << LLONGM1; /* { dg-warning "requires 127 bits to represent" } */
+long long int l11 = LONG_LONG_MIN << 1; /* { dg-warning "requires 65 bits to represent" } */
 
 void
 fn (void)
Index: testsuite/c-c++-common/Wshift-overflow-4.c
===================================================================
--- testsuite/c-c++-common/Wshift-overflow-4.c	(revision 230930)
+++ testsuite/c-c++-common/Wshift-overflow-4.c	(working copy)
@@ -9,6 +9,9 @@
 #define LLONGM1 (sizeof (long long) * __CHAR_BIT__ - 1)
 #define LLONGM2 (sizeof (long long) * __CHAR_BIT__ - 2)
 
+#define INT_MIN (-__INT_MAX__-1)
+#define LONG_LONG_MIN (-__LONG_LONG_MAX__-1)
+
 int i1 = 1 << INTM1;
 int i2 = 9 << INTM1;
 int i3 = 10 << INTM2;
@@ -19,6 +22,7 @@
 int i8 = -10 << INTM2;
 int i9 = -__INT_MAX__ << 2;
 int i10 = -__INT_MAX__ << INTM1;
+int i11 = INT_MIN << 1;
 
 int r1 = 1 >> INTM1;
 int r2 = 9 >> INTM1;
@@ -47,6 +51,7 @@
 long long int l8 = -10LL << LLONGM2;
 long long int l9 = -__LONG_LONG_MAX__ << 2;
 long long int l10 = -__LONG_LONG_MAX__ << LLONGM1;
+long long int l11 = LONG_LONG_MIN << 1;
 
 void
 fn (void)
Index: testsuite/c-c++-common/Wshift-overflow-6.c
===================================================================
--- testsuite/c-c++-common/Wshift-overflow-6.c	(revision 230930)
+++ testsuite/c-c++-common/Wshift-overflow-6.c	(working copy)
@@ -34,3 +34,4 @@
 int i28 = 0b10000000000000000000000000000 << 3;
 int i29 = 0b100000000000000000000000000000 << 2;
 int i30 = 0b1000000000000000000000000000000 << 1;
+int i31 = (int) 0b10000000000000000000000000000000u << 1; /* { dg-warning "requires 33 bits to represent" } */
Index: testsuite/c-c++-common/Wshift-overflow-7.c
===================================================================
--- testsuite/c-c++-common/Wshift-overflow-7.c	(revision 230930)
+++ testsuite/c-c++-common/Wshift-overflow-7.c	(working copy)
@@ -34,3 +34,4 @@
 int i28 = 0b10000000000000000000000000000 << 3; /* { dg-warning "requires 33 bits to represent" } */
 int i29 = 0b100000000000000000000000000000 << 2; /* { dg-warning "requires 33 bits to represent" } */
 int i30 = 0b1000000000000000000000000000000 << 1; /* { dg-warning "requires 33 bits to represent" } */
+int i31 = (int) 0b10000000000000000000000000000000u << 1; /* { dg-warning "requires 33 bits to represent" } */
