diff --git a/gcc/doc/sourcebuild.texi b/gcc/doc/sourcebuild.texi
index c0daf029cbf6c6dd0eae6b8f073e06643584e3f1..28338324f072462787eb990b99d48d5035afeb9c 100644
--- a/gcc/doc/sourcebuild.texi
+++ b/gcc/doc/sourcebuild.texi
@@ -1128,6 +1128,11 @@ by the specified floating-point factor.
 @subsubsection Skip a test for some targets
 
 @table @code
+@item @{ dg-do-if @var{action} @{ @var{selector} @} @}
+Same as dg-do if the selector matches and the test hasn't already been
+marked as unsupported.  Use it to override an action on a target while
+leaving the default action alone for other targets.
+
 @item @{ dg-skip-if @var{comment} @{ @var{selector} @} [@{ @var{include-opts} @} [@{ @var{exclude-opts} @}]] @}
 Arguments @var{include-opts} and @var{exclude-opts} are lists in which
 each element is a string of zero or more GCC options.
diff --git a/gcc/testsuite/gcc.dg/vect/vect-simd-clone-16f.c b/gcc/testsuite/gcc.dg/vect/vect-simd-clone-16f.c
index 7cd29e894d0502a59fadfe67db2db383133022d3..bb3b081b0e3d83ef8ee36960a32e204f83f01bc0 100644
--- a/gcc/testsuite/gcc.dg/vect/vect-simd-clone-16f.c
+++ b/gcc/testsuite/gcc.dg/vect/vect-simd-clone-16f.c
@@ -1,5 +1,7 @@
+/* { dg-do-if compile { target { sse2_runtime && { ! sse4_runtime } } } } */
 /* { dg-require-effective-target vect_simd_clones } */
 /* { dg-additional-options "-fopenmp-simd --param vect-epilogues-nomask=0" } */
+/* { dg-additional-options "-msse4" { target sse4 } } */
 /* { dg-additional-options "-mavx" { target avx_runtime } } */
 /* { dg-additional-options "-mno-avx512f" { target { { i?86*-*-* x86_64-*-* } && { ! lp64 } } } } */
 
diff --git a/gcc/testsuite/gcc.dg/vect/vect-simd-clone-17f.c b/gcc/testsuite/gcc.dg/vect/vect-simd-clone-17f.c
index 177521dc44531479fca1f1a1a0f2010f30fa3fb5..504465614c9897952afbbe3326006976f79a76dd 100644
--- a/gcc/testsuite/gcc.dg/vect/vect-simd-clone-17f.c
+++ b/gcc/testsuite/gcc.dg/vect/vect-simd-clone-17f.c
@@ -1,5 +1,7 @@
+/* { dg-do-if compile { target { sse2_runtime && { ! sse4_runtime } } } } */
 /* { dg-require-effective-target vect_simd_clones } */
 /* { dg-additional-options "-fopenmp-simd --param vect-epilogues-nomask=0" } */
+/* { dg-additional-options "-msse4" { target sse4 } } */
 /* { dg-additional-options "-mavx" { target avx_runtime } } */
 /* { dg-additional-options "-mno-avx512f" { target { { i?86*-*-* x86_64-*-* } && { ! lp64 } } } } */
 
diff --git a/gcc/testsuite/gcc.dg/vect/vect-simd-clone-18f.c b/gcc/testsuite/gcc.dg/vect/vect-simd-clone-18f.c
index 4dd51381d73c0c7c8ec812f24e5054df038059c5..0c418d4324821d231e106ee34a721f2727811e05 100644
--- a/gcc/testsuite/gcc.dg/vect/vect-simd-clone-18f.c
+++ b/gcc/testsuite/gcc.dg/vect/vect-simd-clone-18f.c
@@ -1,5 +1,7 @@
+/* { dg-do-if compile { target { sse2_runtime && { ! sse4_runtime } } } } */
 /* { dg-require-effective-target vect_simd_clones } */
 /* { dg-additional-options "-fopenmp-simd --param vect-epilogues-nomask=0" } */
+/* { dg-additional-options "-msse4" { target sse4 } } */
 /* { dg-additional-options "-mavx" { target avx_runtime } } */
 /* { dg-additional-options "-mno-avx512f" { target { { i?86*-*-* x86_64-*-* } && { ! lp64 } } } } */
 
diff --git a/gcc/testsuite/gcc.dg/vect/vect-simd-clone-20.c b/gcc/testsuite/gcc.dg/vect/vect-simd-clone-20.c
index 9f51a68f3a0c8851af2cd26bd8235c771b851d7d..3e626fc4d4d5632716c22504ceb4ec9a9add7af8 100644
--- a/gcc/testsuite/gcc.dg/vect/vect-simd-clone-20.c
+++ b/gcc/testsuite/gcc.dg/vect/vect-simd-clone-20.c
@@ -1,5 +1,7 @@
+/* { dg-do-if compile { target { sse2_runtime && { ! sse4_runtime } } } } */
 /* { dg-require-effective-target vect_simd_clones } */
 /* { dg-additional-options "-fopenmp-simd --param vect-epilogues-nomask=0" } */
+/* { dg-additional-options "-msse4" { target sse4 } } */
 /* { dg-additional-options "-mavx" { target avx_runtime } } */
 
 /* Test that simd inbranch clones work correctly.  */
@@ -80,8 +82,8 @@ main ()
 }
 
 /* Ensure the the in-branch simd clones are used on targets that support them.  */
-/* { dg-final { scan-tree-dump-times {[\n\r] [^\n]* = foo\.simdclone} 2 "vect" { target { aarch64*-*-* } } } } */
-/* { dg-final { scan-tree-dump-times {[\n\r] [^\n]* = foo\.simdclone} 4 "vect" { target { x86_64*-*-* } } } } */
+/* { dg-final { scan-tree-dump-times {[\n\r] [^\n]* = foo\.simdclone} 2 "vect" { target { aarch64*-*-* || { sse4 && { ! avx_runtime } } } } } } */
+/* { dg-final { scan-tree-dump-times {[\n\r] [^\n]* = foo\.simdclone} 4 "vect" { target { avx_runtime } } } } */
 
 /* The LTO test produces two dump files and we scan the wrong one.  */
 /* { dg-skip-if "" { *-*-* } { "-flto" } { "" } } */
diff --git a/gcc/testsuite/lib/target-supports-dg.exp b/gcc/testsuite/lib/target-supports-dg.exp
index d4ecd1deb914b73c81fdcf6b66d05831de32c33a..c307258db836a89c16cc4d74edabcc08b70f6695 100644
--- a/gcc/testsuite/lib/target-supports-dg.exp
+++ b/gcc/testsuite/lib/target-supports-dg.exp
@@ -393,6 +393,35 @@ proc check-flags { args } {
     return $result
 }
 
+# Override dg-do action on target, without setting the test as
+# unsupported on other targets.  Multiple such overriders can be
+# present.  If the test is already marked as unsupported, it has no
+# effect.  Otherwise, if the target selector matches, call dg-do,
+# otherwise leave dg-do-what alone, so that any earlier setting
+# (possibly the default) prevails.
+
+proc dg-do-if { args } {
+    set args [lreplace $args 0 0]
+    # Verify the number of arguments.
+    if { [llength $args] != 2 } {
+	error "syntax error, need a single action and target selector"
+    }
+
+    # Don't bother if we're already skipping the test.
+    upvar dg-do-what dg-do-what
+    if { [lindex ${dg-do-what} 1] == "N" } {
+	return
+    }
+    
+    # Evaluate selector, return if it does not match.
+    switch [dg-process-target-1 [lindex $args 1]] {
+	"N" { return }
+	"P" { return }
+    }
+
+    eval dg-do $args
+}
+
 # Skip the test (report it as UNSUPPORTED) if the target list and
 # included flags are matched and the excluded flags are not matched.
 #