[llvm] [GlobalIsel] Enabling more rules for fp constant folding (PR #177902)

[Matt Arsenault via llvm-commits]

================
@@ -0,0 +1,167 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
+# RUN: llc -mtriple aarch64 -run-pass=aarch64-prelegalizer-combiner -verify-machineinstrs %s -o - | FileCheck %s
+
+---
+name:            fceil
+body:             |
+  bb.1.entry:
+    ; CHECK-LABEL: name: fceil
+    ; CHECK: %res:_(s64) = G_FCONSTANT double 3.000000e+00
+    ; CHECK-NEXT: $d0 = COPY %res(s64)
+    ; CHECK-NEXT: RET_ReallyLR implicit $d0
+    %a:_(s64) = G_FCONSTANT double 2.5
+    %res:_(s64) = G_FCEIL %a
+    $d0 = COPY %res(s64)
+    RET_ReallyLR implicit $d0
+
+...
+
+---
+name:            fceil_negative
+body:             |
+  bb.1.entry:
+    ; CHECK-LABEL: name: fceil_negative
+    ; CHECK: %res:_(s64) = G_FCONSTANT double -2.000000e+00
+    ; CHECK-NEXT: $d0 = COPY %res(s64)
+    ; CHECK-NEXT: RET_ReallyLR implicit $d0
+    %a:_(s64) = G_FCONSTANT double -2.5
+    %res:_(s64) = G_FCEIL %a
+    $d0 = COPY %res(s64)
+    RET_ReallyLR implicit $d0
+
+...
+
+---
+name:            ffloor
+body:             |
+  bb.1.entry:
----------------
arsenm wrote:

```suggestion
  bb.0:
```

https://github.com/llvm/llvm-project/pull/177902