fix bugzilla Issue 24819 - Optimizer changes result of float calculat…

compiler/src/dmd/backend/cgelem.d

@@ -3888,6 +3888,10 @@
         // If floating point, replace (x = -y) with (x = y ^ signbit)
         if (op2 == OPneg && (tyreal(e2.Ety) || tyimaginary(e2.Ety)) &&
             (e2.E1.Eoper == OPvar || e2.E1.Eoper == OPind) &&
+           /* Turned off for x87 because of https://issues.dlang.org/show_bug.cgi?id=24819
+            * and this is unnecessary anyway because of the FCHS x87 instruction
+            */
+           !config.inline8087 &&
            /* Turned off for XMM registers because they don't play well with
             * int registers.
             */

compiler/src/dmd/backend/debugprint.d

@@ -510,7 +510,7 @@
 @trusted
 void WRfunc(const char* msg, Symbol* sfunc, block* startblock)
 {
-    printf("............%s...%s().............\n", msg, sfunc.Sident.ptr);
+    printf("............%s...%s()\n", msg, sfunc.Sident.ptr);
     numberBlocks(startblock);
     for (block *b = startblock; b; b = b.Bnext)
         WRblock(b);

compiler/src/dmd/backend/dout.d

@@ -861,7 +861,7 @@ private void writefunc2(Symbol *sfunc)
 {
     func_t *f = sfunc.Sfunc;
 
-    //printf("writefunc(%s)\n",sfunc.Sident.ptr);
+    debugb && printf("=========== writefunc %s ==================\n",sfunc.Sident.ptr);
     //symbol_print(sfunc);
     debug debugy && printf("writefunc(%s)\n",sfunc.Sident.ptr);
 

compiler/test/runnable/test24819.d

@@ -0,0 +1,18 @@
+import core.stdc.stdio;
+
+pragma(inline, true)
+double sqrt(double x)
+{
+    static import core.math;
+    return core.math.sqrt(x);
+}
+
+int main()
+{
+    double q = -5.0;
+    double r = q + 1.0;
+    double result = sqrt(-r);
+    //printf("%f\n", result);
+    assert(result == 2);
+    return 0;
+}