[if-converter] Handle BBs that terminate in ret during diamond conversion

This fixes https://llvm.org/PR36825.

Original patch by Valentin Churavy (D45218).

Differential Revision: https://reviews.llvm.org/D45731

llvm-svn: 330345

2 files changed, 59 insertions, 0 deletions

diff --git a/llvm/test/CodeGen/Hexagon/ifcvt-diamond-ret.mir b/llvm/test/CodeGen/Hexagon/ifcvt-diamond-ret.mir
new file mode 100644
index 00000000000..ecf9d3d8319
--- /dev/null
+++ b/llvm/test/CodeGen/Hexagon/ifcvt-diamond-ret.mir
@@ -0,0 +1,25 @@
+# RUN: llc -march=hexagon -run-pass if-converter %s -o - | FileCheck %s
+
+# Make sure this gets if-converted and it doesn't crash.
+# CHECK-LABEL: bb.0
+# CHECK: PS_jmpret $r31
+# CHECK-NOT: bb.{{[1-9]+}}:
+
+---
+name: fred
+tracksRegLiveness: true
+body: |
+  bb.0:
+    successors: %bb.1, %bb.2
+    liveins: $r0
+    renamable $p0 = C2_cmpeqi killed renamable $r0, 0
+    J2_jumpf killed renamable $p0, %bb.2, implicit-def dead $pc
+
+  bb.1:
+    S4_storeiri_io undef renamable $r0, 0, 32768 :: (store 4 into `i32* undef`)
+    PS_jmpret $r31, implicit-def dead $pc
+
+  bb.2:
+    S4_storeiri_io undef renamable $r0, 0, 32768 :: (store 4 into `i32* undef`)
+    PS_jmpret $r31, implicit-def dead $pc
+...
diff --git a/llvm/test/CodeGen/MIR/PowerPC/ifcvt-diamond-ret.mir b/llvm/test/CodeGen/MIR/PowerPC/ifcvt-diamond-ret.mir
new file mode 100644
index 00000000000..bf8ce2b694a
--- /dev/null
+++ b/llvm/test/CodeGen/MIR/PowerPC/ifcvt-diamond-ret.mir
@@ -0,0 +1,34 @@
+# RUN: llc -mtriple=powerpc64le-unknown-linux-gnu -run-pass=if-converter %s -o - | FileCheck %s
+---
+name:           foo
+body:           |
+  bb.0:
+  liveins: $x0, $x3
+  successors: %bb.1(0x40000000), %bb.2(0x40000000)
+
+  dead renamable $x3 = ANDIo8 killed renamable $x3, 1, implicit-def dead $cr0, implicit-def $cr0gt
+  $cr2lt = CROR $cr0gt, $cr0gt
+  BCn killed renamable $cr2lt, %bb.2
+  B %bb.1
+
+  bb.1:
+    renamable $x3 = LIS8 4096
+    MTLR8 $x0, implicit-def $lr8
+    BLR8 implicit $lr8, implicit $rm, implicit $x3
+
+  bb.2:
+    renamable $x3 = LIS8 4096
+    MTLR8 $x0, implicit-def $lr8
+    BLR8 implicit $lr8, implicit $rm, implicit $x3
+...
+
+# Diamond testcase with equivalent branches terminating in returns.
+
+# CHECK: body:             |          
+# CHECK:  bb.0:
+# CHECK:    dead renamable $x3 = ANDIo8 killed renamable $x3, 1, implicit-def dead $cr0, implicit-def $cr0gt
+# CHECK:    $cr2lt = CROR $cr0gt, $cr0gt
+# CHECK:    renamable $x3 = LIS8 4096
+# CHECK:    MTLR8 $x0, implicit-def $lr8
+# CHECK:    BLR8 implicit $lr8, implicit $rm, implicit $x3
+