[SystemZ] Fold more spills

Add a mapping from register-based <INSN>R instructions to the corresponding
memory-based <INSN>.  Use it to cut down on the number of spill loads.

Some instructions extend their operands from smaller fields, so this
required a new TSFlags field to say how big the unextended operand is.

This optimisation doesn't trigger for C(G)R and CL(G)R because in practice
we always combine those instructions with a branch.  Adding a test for every
other case probably seems excessive, but it did catch a missed optimisation
for DSGF (fixed in r185435).


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185529 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 89 insertions, 0 deletions

diff --git a/test/CodeGen/SystemZ/int-cmp-06.ll b/test/CodeGen/SystemZ/int-cmp-06.ll
index efb6ad863c..f8666316d0 100644
--- a/test/CodeGen/SystemZ/int-cmp-06.ll
+++ b/test/CodeGen/SystemZ/int-cmp-06.ll
@@ -2,6 +2,8 @@
 ;
 ; RUN: llc < %s -mtriple=s390x-linux-gnu | FileCheck %s
 
+declare i64 @foo()
+
 ; Check unsigned register comparison.
 define double @f1(double %a, double %b, i64 %i1, i32 %unext) {
 ; CHECK: f1:
@@ -251,3 +253,90 @@ define double @f18(double %a, double %b, i64 %i1, i64 %base, i64 %index) {
   %res = select i1 %cond, double %a, double %b
   ret double %res
 }
+
+; Check that comparisons of spilled values can use CLGF rather than CLGFR.
+define i64 @f19(i32 *%ptr0) {
+; CHECK: f19:
+; CHECK: brasl %r14, foo@PLT
+; CHECK: clgf {{%r[0-9]+}}, 16{{[04]}}(%r15)
+; CHECK: br %r14
+  %ptr1 = getelementptr i32 *%ptr0, i64 2
+  %ptr2 = getelementptr i32 *%ptr0, i64 4
+  %ptr3 = getelementptr i32 *%ptr0, i64 6
+  %ptr4 = getelementptr i32 *%ptr0, i64 8
+  %ptr5 = getelementptr i32 *%ptr0, i64 10
+  %ptr6 = getelementptr i32 *%ptr0, i64 12
+  %ptr7 = getelementptr i32 *%ptr0, i64 14
+  %ptr8 = getelementptr i32 *%ptr0, i64 16
+  %ptr9 = getelementptr i32 *%ptr0, i64 18
+
+  %val0 = load i32 *%ptr0
+  %val1 = load i32 *%ptr1
+  %val2 = load i32 *%ptr2
+  %val3 = load i32 *%ptr3
+  %val4 = load i32 *%ptr4
+  %val5 = load i32 *%ptr5
+  %val6 = load i32 *%ptr6
+  %val7 = load i32 *%ptr7
+  %val8 = load i32 *%ptr8
+  %val9 = load i32 *%ptr9
+
+  %frob0 = add i32 %val0, 100
+  %frob1 = add i32 %val1, 100
+  %frob2 = add i32 %val2, 100
+  %frob3 = add i32 %val3, 100
+  %frob4 = add i32 %val4, 100
+  %frob5 = add i32 %val5, 100
+  %frob6 = add i32 %val6, 100
+  %frob7 = add i32 %val7, 100
+  %frob8 = add i32 %val8, 100
+  %frob9 = add i32 %val9, 100
+
+  store i32 %frob0, i32 *%ptr0
+  store i32 %frob1, i32 *%ptr1
+  store i32 %frob2, i32 *%ptr2
+  store i32 %frob3, i32 *%ptr3
+  store i32 %frob4, i32 *%ptr4
+  store i32 %frob5, i32 *%ptr5
+  store i32 %frob6, i32 *%ptr6
+  store i32 %frob7, i32 *%ptr7
+  store i32 %frob8, i32 *%ptr8
+  store i32 %frob9, i32 *%ptr9
+
+  %ret = call i64 @foo()
+
+  %ext0 = zext i32 %frob0 to i64
+  %ext1 = zext i32 %frob1 to i64
+  %ext2 = zext i32 %frob2 to i64
+  %ext3 = zext i32 %frob3 to i64
+  %ext4 = zext i32 %frob4 to i64
+  %ext5 = zext i32 %frob5 to i64
+  %ext6 = zext i32 %frob6 to i64
+  %ext7 = zext i32 %frob7 to i64
+  %ext8 = zext i32 %frob8 to i64
+  %ext9 = zext i32 %frob9 to i64
+
+  %cmp0 = icmp ult i64 %ret, %ext0
+  %cmp1 = icmp ult i64 %ret, %ext1
+  %cmp2 = icmp ult i64 %ret, %ext2
+  %cmp3 = icmp ult i64 %ret, %ext3
+  %cmp4 = icmp ult i64 %ret, %ext4
+  %cmp5 = icmp ult i64 %ret, %ext5
+  %cmp6 = icmp ult i64 %ret, %ext6
+  %cmp7 = icmp ult i64 %ret, %ext7
+  %cmp8 = icmp ult i64 %ret, %ext8
+  %cmp9 = icmp ult i64 %ret, %ext9
+
+  %sel0 = select i1 %cmp0, i64 %ret, i64 0
+  %sel1 = select i1 %cmp1, i64 %sel0, i64 1
+  %sel2 = select i1 %cmp2, i64 %sel1, i64 2
+  %sel3 = select i1 %cmp3, i64 %sel2, i64 3
+  %sel4 = select i1 %cmp4, i64 %sel3, i64 4
+  %sel5 = select i1 %cmp5, i64 %sel4, i64 5
+  %sel6 = select i1 %cmp6, i64 %sel5, i64 6
+  %sel7 = select i1 %cmp7, i64 %sel6, i64 7
+  %sel8 = select i1 %cmp8, i64 %sel7, i64 8
+  %sel9 = select i1 %cmp9, i64 %sel8, i64 9
+
+  ret i64 %sel9
+}