X86: When lowering shl_parts, don't emit shift amounts larger than the bit width.

While it's safe for the X86-specific shift nodes, dag combining will
kill generic nodes. Insert an AND to make it safe, isel will nuke it
as x86's shift instructions have an implicit AND.

Fixes PR16108, which contains a contraption to hit this case in between
constant folders.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@197228 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 28 insertions, 0 deletions

diff --git a/test/CodeGen/X86/legalize-shift-64.ll b/test/CodeGen/X86/legalize-shift-64.ll
index 77364688af..64460bb911 100644
--- a/test/CodeGen/X86/legalize-shift-64.ll
+++ b/test/CodeGen/X86/legalize-shift-64.ll
@@ -64,3 +64,31 @@ define <2 x i64> @test5(<2 x i64> %A, <2 x i64> %B) {
 ; CHECK: shl
 ; CHECK: shldl
 }
+
+; PR16108
+define i32 @test6() {
+  %x = alloca i32, align 4
+  %t = alloca i64, align 8
+  store i32 1, i32* %x, align 4
+  store i64 1, i64* %t, align 8  ;; DEAD
+  %load = load i32* %x, align 4
+  %shl = shl i32 %load, 8
+  %add = add i32 %shl, -224
+  %sh_prom = zext i32 %add to i64
+  %shl1 = shl i64 1, %sh_prom
+  %cmp = icmp ne i64 %shl1, 4294967296
+  br i1 %cmp, label %if.then, label %if.end
+
+if.then:                                          ; preds = %entry
+  ret i32 1
+
+if.end:                                           ; preds = %entry
+  ret i32 0
+
+; CHECK-LABEL: test6:
+; CHECK-NOT: andb $31
+; CHECK: sete
+; CHECK: movzbl
+; CHECK: xorl $1
+; CHECK: orl
+}