[clang] [flang] [llvm] [openmp] [Clang][OpenMP][LoopTransformations] Add support for "#pragma omp fuse" loop transformation direcrive and "looprange" clause (PR #139293)

[Alexey Bataev via llvm-commits]

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@@ -0,0 +1,186 @@
+// RUN: %clang_cc1 -triple x86_64-pc-linux-gnu -std=c++20 -fopenmp -fopenmp-version=60 -fsyntax-only -Wuninitialized -verify %s
+
+void func() {
+
+    // expected-error at +2 {{statement after '#pragma omp fuse' must be a loop sequence containing canonical loops or loop-generating constructs}}
+    #pragma omp fuse 
+    ;
+
+    // expected-error at +2 {{statement after '#pragma omp fuse' must be a for loop}}
+    #pragma omp fuse 
+    {int bar = 0;}
+
+    // expected-error at +4 {{statement after '#pragma omp fuse' must be a for loop}}
+    #pragma omp fuse 
+    {
+        for(int i = 0; i < 10; ++i);
+        int x = 2;
+    }
+
+    // expected-error at +2 {{statement after '#pragma omp fuse' must be a loop sequence containing canonical loops or loop-generating constructs}}
+    #pragma omp fuse 
+    #pragma omp for 
+    for (int i = 0; i < 7; ++i)
+        ;
+
+    {
+        // expected-error at +2 {{expected statement}}
+        #pragma omp fuse
+    }
+
+    // expected-warning at +1 {{extra tokens at the end of '#pragma omp fuse' are ignored}}
+    #pragma omp fuse foo
+    {
+        for (int i = 0; i < 7; ++i)
+            ;
+        for(int j = 0; j < 100; ++j);
+
+    }
+
+
+    // expected-error at +1 {{unexpected OpenMP clause 'final' in directive '#pragma omp fuse'}}
+    #pragma omp fuse final(0) 
+    {
+        for (int i = 0; i < 7; ++i)
+            ;
+        for(int j = 0; j < 100; ++j);
+
+    }
+
+    //expected-error at +4 {{loop after '#pragma omp fuse' is not in canonical form}}
----------------
alexey-bataev wrote:

Why do you need the second message, if there's already another one, requiring canonical loop form?

https://github.com/llvm/llvm-project/pull/139293