Add testcases for PR30188

[sebpop]

Summary

Add testcases to clang test/ to make sure that the combined middle-end
optimizations do not regress on optimizing the number of loads in the loops.

[davidxl]

clang/test/CodeGen/pr30188.c

3

Can you just do

... | grep load | count 3

7

Also check there is no store

clang/test/CodeGenCXX/pr30188.cpp

5

check no store as well?

[rsmith]

This belongs in LLVM's test suite, not Clang's.

[sebpop]

Agreed, this is a test for llvm/opt.
I will submit another patch.

clang/test/CodeGen/pr30188.c

+// RUN: %clang_cc1 -O2 -emit-llvm -o - %s | FileCheck %s
+
+// Check that optimizers are able to optimize the number of loads in the loop.
+// CHECK: load
+// CHECK: load
+// CHECK: load
+// CHECK-NOT: load
+
+struct b {
+  int x_;
+};
+
+struct a {
+  int l_;
+  struct b *data_;
+};
+
+int BinarySearch(struct a *input, struct b t) {
+  if (input->l_ > 0) {
+    int low = 0;
+    int high = input->l_;
+    while (high != low + 1) {
+      int mid = (high + low) / 2;
+      if (input->data_[mid].x_ > t.x_)
+        high = mid;
+      else
+        low = mid;
+    }
+    return low;
+  }
+  return -1;
+}

clang/test/CodeGenCXX/pr30188.cpp

+// RUN: %clang_cc1 -O2 -emit-llvm -o - %s | FileCheck %s
+
+// Check that optimizers are able to optimize the number of loads in the loop.
+// CHECK: load
+// CHECK-NOT: load
+
+int test(float exp, float *array) {
+  int hi = 255;
+  int lo = 0;
+  int offset = 0;
+
+  while(hi > lo) {
+    unsigned delta = (hi - lo) / 2u;
+    delta = 1u > delta ? 1u : delta;
+    offset = lo + delta;
+
+    if (array[offset] > exp)
+      hi = hi - delta;
+    else
+      lo = lo + delta;
+  }
+
+  return offset;
+}