diff --git a/.travis.yml b/.travis.yml
index c2e61f35..938dce2e 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -71,53 +71,53 @@ jobs:
 
     # Start with three completely different environments, to get errors asap.
 
-    - name: "GCC 10 -O3"
+    - name: "GCC 11 -O3"
       stage: check
       os: linux
       dist: bionic
-      addons: &gcc10
+      addons: &gcc11
         apt:
           sources:
             # See https://github.com/travis-ci/apt-source-safelist/issues/410.
             - sourceline: 'ppa:ubuntu-toolchain-r/test'
-          packages: g++-10
+          packages: g++-11
       env:
-        - CC=gcc-10
-        - CXX=g++-10
+        - CC=gcc-11
+        - CXX=g++-11
         - CONFIGUREFLAGS='CPPFLAGS=-DNDEBUG CFLAGS=-O3 CXXFLAGS=-O3'
 
     # ASAN is time consuming, and we timeout the 50min granted by
     # Travis if we run all the tests in one go.  Run in two parts.
-    - name: "Clang 10 libc++ and ASAN part 1"
+    - name: "Clang 11 libc++ and ASAN part 1"
       stage: check
       os: linux
       dist: bionic
-      addons: &clang10
+      addons: &clang11
         apt:
           sources:
             # See https://github.com/travis-ci/apt-source-safelist/issues/410.
             - sourceline: 'ppa:ubuntu-toolchain-r/test'
-            - sourceline: 'deb http://apt.llvm.org/bionic/ llvm-toolchain-bionic-10 main'
+            - sourceline: 'deb http://apt.llvm.org/bionic/ llvm-toolchain-bionic-11 main'
               key_url: 'https://apt.llvm.org/llvm-snapshot.gpg.key'
           packages:
-            - clang-10
-            - libc++-10-dev
-            - libc++abi-10-dev
+            - clang-11
+            - libc++-11-dev
+            - libc++abi-11-dev
       env:
         # Do not use ASAN with ubuntu's libc++: https://bugs.llvm.org/show_bug.cgi?id=17379
-        - CC='clang-10 -fsanitize=address'
-        - CXX='clang++-10 -fsanitize=address -stdlib=libc++'
+        - CC='clang-11 -fsanitize=address'
+        - CXX='clang++-11 -fsanitize=address -stdlib=libc++'
         - PART=1
 
-    - name: "Clang 10 libc++ and ASAN part 2"
+    - name: "Clang 11 libc++ and ASAN part 2"
       stage: check
       os: linux
       dist: bionic
-      addons: *clang10
+      addons: *clang11
       env:
         # Do not use ASAN with ubuntu's libc++: https://bugs.llvm.org/show_bug.cgi?id=17379
-        - CC='clang-10 -fsanitize=address'
-        - CXX='clang++-10 -fsanitize=address -stdlib=libc++'
+        - CC='clang-11 -fsanitize=address'
+        - CXX='clang++-11 -fsanitize=address -stdlib=libc++'
         - PART=2
 
     # See https://github.com/simd-everywhere/simde/blob/master/.travis.yml
@@ -139,19 +139,19 @@ jobs:
           packages:
           - intel-oneapi-icc
 
-    - name: "ARM64: GCC 10 -O2 part 1"
+    - name: "ARM64: GCC 11 -O2 part 1"
       stage: check
       os: linux
       arch: arm64
       dist: bionic
-      addons: *gcc10
+      addons: *gcc11
       env:
-        - CC=gcc-10
-        - CXX=g++-10
+        - CC=gcc-11
+        - CXX=g++-11
         - CONFIGUREFLAGS='CPPFLAGS=-DNDEBUG CFLAGS=-O2 CXXFLAGS=-O2'
         - PART=1
 
-    - name: "PPC64le: GCC 10 -O2 part 1"
+    - name: "PPC64le: GCC 11 -O2 part 1"
       stage: check
       os: linux
       arch: ppc64le
@@ -161,22 +161,22 @@ jobs:
           sources:
             # See https://github.com/travis-ci/apt-source-safelist/issues/410.
             - sourceline: 'ppa:ubuntu-toolchain-r/test'
-          packages: g++-10
+          packages: g++-11
       env:
-        - CC=gcc-10
-        - CXX=g++-10
+        - CC=gcc-11
+        - CXX=g++-11
         - CONFIGUREFLAGS='CFLAGS=-O2 CXXFLAGS=-O2'
         - PART=1
 
-    - name: "s390x: GCC 10 -O2 part 1"
+    - name: "s390x: GCC 11 -O2 part 1"
       stage: check
       os: linux
       arch: s390x
       dist: bionic
-      addons: *gcc10
+      addons: *gcc11
       env:
-        - CC=gcc-10
-        - CXX=g++-10
+        - CC=gcc-11
+        - CXX=g++-11
         - CONFIGUREFLAGS='CFLAGS=-O2 CXXFLAGS=-O2'
         - PART=1
 
@@ -184,7 +184,7 @@ jobs:
     ## GCC.  ##
     ## ----- ##
 
-    - name: "GCC 9 with sanitizers part 1"
+    - name: "GCC 10 with sanitizers part 1"
       stage: check
       os: linux
       dist: bionic
@@ -193,11 +193,24 @@ jobs:
           sources:
             # See https://github.com/travis-ci/apt-source-safelist/issues/410.
             - sourceline: 'ppa:ubuntu-toolchain-r/test'
+          packages: g++-10
+      env:
+        - CC='gcc-10 -fsanitize=undefined,address -fno-omit-frame-pointer'
+        - CXX='g++-10 -fsanitize=undefined,address -fno-omit-frame-pointer'
+        - CONFIGUREFLAGS='CFLAGS=-O1 CXXFLAGS=-O1'
+        - PART=1
+
+    # With glr2.cc, we run out of time with the full test suite.
+    - name: "GCC 9 part 1"
+      stage: check
+      os: linux
+      dist: bionic
+      addons:
+        apt:
           packages: g++-9
       env:
-        - CC='gcc-9 -fsanitize=undefined,address -fno-omit-frame-pointer'
-        - CXX='g++-9 -fsanitize=undefined,address -fno-omit-frame-pointer'
-        - CONFIGUREFLAGS='CFLAGS=-O1 CXXFLAGS=-O1'
+        - CC=gcc-9
+        - CXX=g++-9
         - PART=1
 
     # With glr2.cc, we run out of time with the full test suite.
@@ -300,7 +313,27 @@ jobs:
     ## Clang.  ##
     ## ------- ##
 
-    - name: "Clang 9 -O3"
+    - name: "Clang 10 -O3 and libc++"
+      stage: check
+      os: linux
+      dist: bionic
+      addons:
+        apt:
+          sources:
+            # See https://github.com/travis-ci/apt-source-safelist/issues/410.
+            - sourceline: 'ppa:ubuntu-toolchain-r/test'
+            - sourceline: 'deb http://apt.llvm.org/bionic/ llvm-toolchain-bionic-10 main'
+              key_url: 'https://apt.llvm.org/llvm-snapshot.gpg.key'
+          packages:
+            - clang-10
+            - libc++-10-dev
+            - libc++abi-10-dev
+      env:
+        - CC='clang-10'
+        - CXX='clang++-10 -stdlib=libc++'
+        - CONFIGUREFLAGS='CPPFLAGS=-DNDEBUG CFLAGS=-O3 CXXFLAGS=-O3'
+
+    - name: "Clang 9 and libc++"
       stage: check
       os: linux
       dist: bionic
@@ -318,9 +351,8 @@ jobs:
       env:
         - CC='clang-9'
         - CXX='clang++-9 -stdlib=libc++'
-        - CONFIGUREFLAGS='CPPFLAGS=-DNDEBUG CFLAGS=-O3 CXXFLAGS=-O3'
 
-    - name: "Clang 8"
+    - name: "Clang 8 and libc++"
       stage: check
       os: linux
       dist: bionic
@@ -334,7 +366,7 @@ jobs:
         - CC=clang-8
         - CXX='clang++-8 -stdlib=libc++'
 
-    - name: "Clang 7"
+    - name: "Clang 7 and libc++"
       stage: check
       os: linux
       dist: bionic