[ARM] Materialise some boolean values to avoid a branch
This patch combines some cases of ARMISD::CMOV for integers that arise in comparisons of the form
a != b ? x : 0
a == b ? 0 : x
and that currently (e.g. in Thumb1) are emitted as branches.
Differential Revision: https://reviews.llvm.org/D34515
llvm-svn: 325323
diff --git a/llvm/test/CodeGen/ARM/cmp.ll b/llvm/test/CodeGen/ARM/cmp.ll
index e12a096..5c16309 100644
--- a/llvm/test/CodeGen/ARM/cmp.ll
+++ b/llvm/test/CodeGen/ARM/cmp.ll
@@ -3,42 +3,35 @@
define i1 @f1(i32 %a, i32 %b) {
; CHECK-LABEL: f1:
-; CHECK: mov r2, #0
-; CHECK: cmp r0, r1
-; CHECK: movwne r2, #1
-; CHECK: mov r0, r2
-; CHECK-T2: mov{{.*}} r2, #0
-; CHECK-T2: cmp r0, r1
-; CHECK-T2: movne r2, #1
-; CHECK-T2: mov r0, r2
+; CHECK: subs r0, r0, r1
+; CHECK: movwne r0, #1
+; CHECK-T2: subs r0, r0, r1
+; CHECK-T2: it ne
+; CHECK-T2: movne r0, #1
%tmp = icmp ne i32 %a, %b
ret i1 %tmp
}
define i1 @f2(i32 %a, i32 %b) {
; CHECK-LABEL: f2:
-; CHECK: mov r2, #0
-; CHECK: cmp r0, r1
-; CHECK: movweq r2, #1
-; CHECK: mov r0, r2
-; CHECK-T2: mov{{.*}} r2, #0
-; CHECK-T2: cmp r0, r1
-; CHECK-T2: moveq r2, #1
-; CHECK-T2: mov r0, r2
+; CHECK: sub r0, r0, r1
+; CHECK: clz r0, r0
+; CHECK: lsr r0, r0, #5
+; CHECK-T2: subs r0, r0, r1
+; CHECK-T2: clz r0, r0
+; CHECK-T2: lsrs r0, r0, #5
%tmp = icmp eq i32 %a, %b
ret i1 %tmp
}
define i1 @f6(i32 %a, i32 %b) {
; CHECK-LABEL: f6:
-; CHECK: mov r2, #0
-; CHECK: cmp {{.*}}, r1, lsl #5
-; CHECK: movweq r2, #1
-; CHECK: mov r0, r2
-; CHECK-T2: mov{{.*}} r2, #0
-; CHECK-T2: cmp.w r0, r1, lsl #5
-; CHECK-T2: moveq r2, #1
-; CHECK-T2: mov r0, r2
+; CHECK: sub r0, r0, r1, lsl #5
+; CHECK: clz r0, r0
+; CHECK: lsr r0, r0, #5
+; CHECK-T2: sub.w r0, r0, r1, lsl #5
+; CHECK-T2: clz r0, r0
+; CHECK-T2: lsrs r0, r0, #5
%tmp = shl i32 %b, 5
%tmp1 = icmp eq i32 %a, %tmp
ret i1 %tmp1
@@ -46,14 +39,15 @@
define i1 @f7(i32 %a, i32 %b) {
; CHECK-LABEL: f7:
-; CHECK: mov r2, #0
-; CHECK: cmp r0, r1, lsr #6
-; CHECK: movwne r2, #1
-; CHECK: mov r0, r2
-; CHECK-T2: mov{{.*}} r2, #0
-; CHECK-T2: cmp.w r0, r1, lsr #6
-; CHECK-T2: movne r2, #1
-; CHECK-T2: mov r0, r2
+; CHECK: sub r2, r0, r1, lsr #6
+; CHECK: cmp r0, r1, lsr #6
+; CHECK: movwne r2, #1
+; CHECK: mov r0, r2
+; CHECK-T2: sub.w r2, r0, r1, lsr #6
+; CHECK-T2: cmp.w r0, r1, lsr #6
+; CHECK-T2: it ne
+; CHECK-T2: movne r2, #1
+; CHECK-T2: mov r0, r2
%tmp = lshr i32 %b, 6
%tmp1 = icmp ne i32 %a, %tmp
ret i1 %tmp1
@@ -61,14 +55,12 @@
define i1 @f8(i32 %a, i32 %b) {
; CHECK-LABEL: f8:
-; CHECK: mov r2, #0
-; CHECK: cmp r0, r1, asr #7
-; CHECK: movweq r2, #1
-; CHECK: mov r0, r2
-; CHECK-T2: mov{{.*}} r2, #0
-; CHECK-T2: cmp.w r0, r1, asr #7
-; CHECK-T2: moveq r2, #1
-; CHECK-T2: mov r0, r2
+; CHECK: sub r0, r0, r1, asr #7
+; CHECK: clz r0, r0
+; CHECK: lsr r0, r0, #5
+; CHECK-T2: sub.w r0, r0, r1, asr #7
+; CHECK-T2: clz r0, r0
+; CHECK-T2: lsrs r0, r0, #5
%tmp = ashr i32 %b, 7
%tmp1 = icmp eq i32 %a, %tmp
ret i1 %tmp1
@@ -76,14 +68,15 @@
define i1 @f9(i32 %a) {
; CHECK-LABEL: f9:
-; CHECK: mov r1, #0
-; CHECK: cmp r0, r0, ror #8
-; CHECK: movwne r1, #1
-; CHECK: mov r0, r1
-; CHECK-T2: mov{{.*}} r1, #0
-; CHECK-T2: cmp.w r0, r0, ror #8
-; CHECK-T2: movne r1, #1
-; CHECK-T2: mov r0, r1
+; CHECK: sub r1, r0, r0, ror #8
+; CHECK: cmp r0, r0, ror #8
+; CHECK: movwne r1, #1
+; CHECK: mov r0, r1
+; CHECK-T2: sub.w r1, r0, r0, ror #8
+; CHECK-T2: cmp.w r0, r0, ror #8
+; CHECK-T2: it ne
+; CHECK-T2: movne r1, #1
+; CHECK-T2: mov r0, r1
%l8 = shl i32 %a, 24
%r8 = lshr i32 %a, 8
%tmp = or i32 %l8, %r8