[InstCombine] add tests for trunc(load); NFC

I'm not sure if transforming any of these is valid as
a target-independent fold, but we might as well have
a few tests here to confirm or deny our position.

llvm-svn: 365523

1 files changed, 73 insertions, 0 deletions

diff --git a/llvm/test/Transforms/InstCombine/trunc-load.ll b/llvm/test/Transforms/InstCombine/trunc-load.ll
new file mode 100644
index 00000000000..8088ce1b7de
--- /dev/null
+++ b/llvm/test/Transforms/InstCombine/trunc-load.ll
@@ -0,0 +1,73 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt < %s -instcombine -S -data-layout="e-n16:32:64" | FileCheck %s --check-prefixes=CHECK,LE
+; RUN: opt < %s -instcombine -S -data-layout="E-n16:32:64" | FileCheck %s --check-prefixes=CHECK,BE
+
+define i32 @truncload(i64* %ptr) {
+; CHECK-LABEL: @truncload(
+; CHECK-NEXT:    [[X:%.*]] = load i64, i64* [[PTR:%.*]], align 4
+; CHECK-NEXT:    [[R:%.*]] = trunc i64 [[X]] to i32
+; CHECK-NEXT:    ret i32 [[R]]
+;
+  %x = load i64, i64* %ptr
+  %r = trunc i64 %x to i32
+  ret i32 %r
+}
+
+define i16 @truncload_align(i32* %ptr) {
+; CHECK-LABEL: @truncload_align(
+; CHECK-NEXT:    [[X:%.*]] = load i32, i32* [[PTR:%.*]], align 16
+; CHECK-NEXT:    [[R:%.*]] = trunc i32 [[X]] to i16
+; CHECK-NEXT:    ret i16 [[R]]
+;
+  %x = load i32, i32* %ptr, align 16
+  %r = trunc i32 %x to i16
+  ret i16 %r
+}
+
+declare void @use(i64)
+
+define i32 @truncload_extra_use(i64* %ptr) {
+; CHECK-LABEL: @truncload_extra_use(
+; CHECK-NEXT:    [[X:%.*]] = load i64, i64* [[PTR:%.*]], align 2
+; CHECK-NEXT:    call void @use(i64 [[X]])
+; CHECK-NEXT:    [[R:%.*]] = trunc i64 [[X]] to i32
+; CHECK-NEXT:    ret i32 [[R]]
+;
+  %x = load i64, i64* %ptr, align 2
+  call void @use(i64 %x)
+  %r = trunc i64 %x to i32
+  ret i32 %r
+}
+
+define i8 @truncload_type(i64* %ptr) {
+; CHECK-LABEL: @truncload_type(
+; CHECK-NEXT:    [[X:%.*]] = load i64, i64* [[PTR:%.*]], align 2
+; CHECK-NEXT:    [[R:%.*]] = trunc i64 [[X]] to i8
+; CHECK-NEXT:    ret i8 [[R]]
+;
+  %x = load i64, i64* %ptr, align 2
+  %r = trunc i64 %x to i8
+  ret i8 %r
+}
+
+define i32 @truncload_volatile(i64* %ptr) {
+; CHECK-LABEL: @truncload_volatile(
+; CHECK-NEXT:    [[X:%.*]] = load volatile i64, i64* [[PTR:%.*]], align 8
+; CHECK-NEXT:    [[R:%.*]] = trunc i64 [[X]] to i32
+; CHECK-NEXT:    ret i32 [[R]]
+;
+  %x = load volatile i64, i64* %ptr, align 8
+  %r = trunc i64 %x to i32
+  ret i32 %r
+}
+
+define i32 @truncload_address_space(i64 addrspace(1)* %ptr) {
+; CHECK-LABEL: @truncload_address_space(
+; CHECK-NEXT:    [[X:%.*]] = load i64, i64 addrspace(1)* [[PTR:%.*]], align 4
+; CHECK-NEXT:    [[R:%.*]] = trunc i64 [[X]] to i32
+; CHECK-NEXT:    ret i32 [[R]]
+;
+  %x = load i64, i64 addrspace(1)* %ptr, align 4
+  %r = trunc i64 %x to i32
+  ret i32 %r
+}