[DAGCombiner] fold sext into negation

As noted in D59818:
  %z = zext i8 %x to i32
  %neg = sub i32 0, %z
  %r = sext i32 %neg to i64
  =>
  %z2 = zext i8 %x to i64
  %r = sub i64 0, %z2

https://rise4fun.com/Alive/KzSR

llvm-svn: 357178

1 files changed, 5 insertions, 10 deletions

diff --git a/llvm/test/CodeGen/X86/vector-compare-any_of.ll b/llvm/test/CodeGen/X86/vector-compare-any_of.ll
index 4bda687699d..d24df0a4f6a 100644
--- a/llvm/test/CodeGen/X86/vector-compare-any_of.ll
+++ b/llvm/test/CodeGen/X86/vector-compare-any_of.ll
@@ -84,8 +84,7 @@ define i64 @test_v4f64_legal_sext(<4 x double> %a0, <4 x double> %a1) {
 ; SSE-NEXT:    packssdw %xmm3, %xmm2
 ; SSE-NEXT:    movmskps %xmm2, %eax
 ; SSE-NEXT:    negl %eax
-; SSE-NEXT:    sbbl %eax, %eax
-; SSE-NEXT:    cltq
+; SSE-NEXT:    sbbq %rax, %rax
 ; SSE-NEXT:    retq
 ;
 ; AVX-LABEL: test_v4f64_legal_sext:
@@ -95,8 +94,7 @@ define i64 @test_v4f64_legal_sext(<4 x double> %a0, <4 x double> %a1) {
 ; AVX-NEXT:    vpackssdw %xmm1, %xmm0, %xmm0
 ; AVX-NEXT:    vmovmskps %xmm0, %eax
 ; AVX-NEXT:    negl %eax
-; AVX-NEXT:    sbbl %eax, %eax
-; AVX-NEXT:    cltq
+; AVX-NEXT:    sbbq %rax, %rax
 ; AVX-NEXT:    vzeroupper
 ; AVX-NEXT:    retq
 ;
@@ -346,8 +344,7 @@ define i64 @test_v4i64_legal_sext(<4 x i64> %a0, <4 x i64> %a1) {
 ; SSE-NEXT:    packssdw %xmm1, %xmm0
 ; SSE-NEXT:    movmskps %xmm0, %eax
 ; SSE-NEXT:    negl %eax
-; SSE-NEXT:    sbbl %eax, %eax
-; SSE-NEXT:    cltq
+; SSE-NEXT:    sbbq %rax, %rax
 ; SSE-NEXT:    retq
 ;
 ; AVX1-LABEL: test_v4i64_legal_sext:
@@ -359,8 +356,7 @@ define i64 @test_v4i64_legal_sext(<4 x i64> %a0, <4 x i64> %a1) {
 ; AVX1-NEXT:    vpackssdw %xmm2, %xmm0, %xmm0
 ; AVX1-NEXT:    vmovmskps %xmm0, %eax
 ; AVX1-NEXT:    negl %eax
-; AVX1-NEXT:    sbbl %eax, %eax
-; AVX1-NEXT:    cltq
+; AVX1-NEXT:    sbbq %rax, %rax
 ; AVX1-NEXT:    vzeroupper
 ; AVX1-NEXT:    retq
 ;
@@ -371,8 +367,7 @@ define i64 @test_v4i64_legal_sext(<4 x i64> %a0, <4 x i64> %a1) {
 ; AVX2-NEXT:    vpackssdw %xmm1, %xmm0, %xmm0
 ; AVX2-NEXT:    vmovmskps %xmm0, %eax
 ; AVX2-NEXT:    negl %eax
-; AVX2-NEXT:    sbbl %eax, %eax
-; AVX2-NEXT:    cltq
+; AVX2-NEXT:    sbbq %rax, %rax
 ; AVX2-NEXT:    vzeroupper
 ; AVX2-NEXT:    retq
 ;