[InstCombine] add tests for extract of vector load; NFC

There's a mismatch internally about how we are handling these patterns. 
We count loads as cheapToScalarize(), but then we don't actually 
scalarize them, so that can leave extra instructions compared to where 
we started when scalarizing other ops. If it's cheapToScalarize, then 
we should be scalarizing.

llvm-svn: 349560

1 files changed, 57 insertions, 0 deletions

diff --git a/llvm/test/Transforms/InstCombine/scalarization.ll b/llvm/test/Transforms/InstCombine/scalarization.ll
index a5c5600f0d2..586509542b8 100644
--- a/llvm/test/Transforms/InstCombine/scalarization.ll
+++ b/llvm/test/Transforms/InstCombine/scalarization.ll
@@ -1,6 +1,63 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
 ; RUN: opt -instcombine -S < %s | FileCheck %s
 
+define i32 @extract_load(<4 x i32>* %p) {
+; CHECK-LABEL: @extract_load(
+; CHECK-NEXT:    [[X:%.*]] = load <4 x i32>, <4 x i32>* [[P:%.*]], align 4
+; CHECK-NEXT:    [[EXT:%.*]] = extractelement <4 x i32> [[X]], i32 1
+; CHECK-NEXT:    ret i32 [[EXT]]
+;
+  %x = load <4 x i32>, <4 x i32>* %p, align 4
+  %ext = extractelement <4 x i32> %x, i32 1
+  ret i32 %ext
+}
+
+define double @extract_load_fp(<4 x double>* %p) {
+; CHECK-LABEL: @extract_load_fp(
+; CHECK-NEXT:    [[X:%.*]] = load <4 x double>, <4 x double>* [[P:%.*]], align 32
+; CHECK-NEXT:    [[EXT:%.*]] = extractelement <4 x double> [[X]], i32 3
+; CHECK-NEXT:    ret double [[EXT]]
+;
+  %x = load <4 x double>, <4 x double>* %p, align 32
+  %ext = extractelement <4 x double> %x, i32 3
+  ret double %ext
+}
+
+define double @extract_load_volatile(<4 x double>* %p) {
+; CHECK-LABEL: @extract_load_volatile(
+; CHECK-NEXT:    [[X:%.*]] = load volatile <4 x double>, <4 x double>* [[P:%.*]], align 32
+; CHECK-NEXT:    [[EXT:%.*]] = extractelement <4 x double> [[X]], i32 2
+; CHECK-NEXT:    ret double [[EXT]]
+;
+  %x = load volatile <4 x double>, <4 x double>* %p
+  %ext = extractelement <4 x double> %x, i32 2
+  ret double %ext
+}
+
+define double @extract_load_extra_use(<4 x double>* %p, <4 x double>* %p2) {
+; CHECK-LABEL: @extract_load_extra_use(
+; CHECK-NEXT:    [[X:%.*]] = load <4 x double>, <4 x double>* [[P:%.*]], align 8
+; CHECK-NEXT:    [[EXT:%.*]] = extractelement <4 x double> [[X]], i32 0
+; CHECK-NEXT:    store <4 x double> [[X]], <4 x double>* [[P2:%.*]], align 32
+; CHECK-NEXT:    ret double [[EXT]]
+;
+  %x = load <4 x double>, <4 x double>* %p, align 8
+  %ext = extractelement <4 x double> %x, i32 0
+  store <4 x double> %x, <4 x double>* %p2
+  ret double %ext
+}
+
+define double @extract_load_variable_index(<4 x double>* %p, i32 %y) {
+; CHECK-LABEL: @extract_load_variable_index(
+; CHECK-NEXT:    [[X:%.*]] = load <4 x double>, <4 x double>* [[P:%.*]], align 32
+; CHECK-NEXT:    [[EXT:%.*]] = extractelement <4 x double> [[X]], i32 [[Y:%.*]]
+; CHECK-NEXT:    ret double [[EXT]]
+;
+  %x = load <4 x double>, <4 x double>* %p
+  %ext = extractelement <4 x double> %x, i32 %y
+  ret double %ext
+}
+
 define void @scalarize_phi(i32 * %n, float * %inout) {
 ; CHECK-LABEL: @scalarize_phi(
 ; CHECK-NEXT:  entry: